Redesign phase C: claim flow, limited manage page, device protocol

The frame-claiming pipeline, end to end. Firmware: every request now
carries ?id=<12-hex STA MAC> via build_url (mirrored in build_ota_url),
and the captive portal's success page became a redirect that hands the
user's browser to <server>/claim?device_id=... after ~7s -- enough time
for the phone to drop the provisioning AP while the device reboots.
The server pushes a per-frame device token through /frame/config during
a one-time handshake; the firmware persists it to NVS (a dedicated
single-key write that deliberately doesn't reset the connected-once
flag or WiFi cache) and prefers it over the provisioned shared token
from the next request on. Config response buffer grows 256->512. Both
board variants compile clean; new firmware also works against an old
server (which ignores ?id=) and old firmware against this server (the
phase A legacy mapping), so either deploy order survives.

Server: /claim lands the captive-portal redirect -- claim-gated signup
(a valid unclaimed/unregistered device id IS the enrollment invitation),
pending claims for the user-beats-the-frame race (auto-attached at
self-registration, 24h expiry), and a waiting page that refreshes until
the frame checks in. Unclaimed/unconfigured frames get a rendered
instruction placeholder with a QR from /frame/image (200, never an
error loop) -- new qrcode dep, placeholder shares the exact
quantize/pack path photos use.

The on-frame manage QR now resolves to a limited no-login page: scans
of / carrying device credentials (new ?id&token or the legacy shared
token) 303 to /m/<manage_token>, which allows exactly view queue,
show-next, advance, back, and scoped thumbnails -- no settings, no
removal, no other frames. Full control means logging in.

One real protocol hole found by simulating full wake cycles: after
self-registration the device could never authenticate again (the wake
cycle fetches the image BEFORE /frame/config delivers its token).
require_device now treats the id itself as the credential until the
first authenticated request flips device_token_ack -- the same trust
level as open registration, closing permanently once the handshake
completes.

server/app/auth.py

@@ -265,8 +265,20 @@ def require_device(request: Request, db: Session = Depends(get_db)) -> Frame:
             if token_ok and not frame.device_token_ack:
                 frame.device_token_ack = True
                 logger.info("Frame #%d acknowledged its device token", frame.id)
-            if not token_ok and not (frame.legacy_token_enabled and legacy_ok):
-                raise HTTPException(401, "Missing or invalid access token")
+            if not token_ok:
+                if frame.legacy_token_enabled and legacy_ok:
+                    pass
+                elif not frame.device_token_ack:
+                    # Handshake window: the device registered but hasn't
+                    # received its token yet (the wake cycle fetches the
+                    # image BEFORE polling /frame/config, where the token
+                    # is delivered) -- the id stays the credential, same
+                    # trust level as the open registration that created
+                    # the row. Closes permanently on the first
+                    # authenticated request.
+                    pass
+                else:
+                    raise HTTPException(401, "Missing or invalid access token")
     else:
         if not legacy_ok:
             raise HTTPException(401, "Missing or invalid access token")

server/app/image_pipeline.py

@@ -174,7 +174,15 @@ def render_frame(source: Image.Image, faces: list[dict] | None = None,
     else:
         fitted = ImageOps.fit(fitted, (logical_w, logical_h), method=Image.LANCZOS)
 
-    quantized = fitted.quantize(palette=_PALETTE_IMAGE, dither=Image.Dither.FLOYDSTEINBERG)
+    return _quantize_and_pack(fitted, orientation)
+
+
+def _quantize_and_pack(logical_img: Image.Image, orientation: str) -> bytes:
+    """The shared back half of rendering: 6-color Floyd-Steinberg
+    quantization, rotation into native panel space, and 2-pixels/byte
+    packing. Takes an RGB image already composed at logical_render_size()
+    for the orientation."""
+    quantized = logical_img.quantize(palette=_PALETTE_IMAGE, dither=Image.Dither.FLOYDSTEINBERG)
     transpose = ORIENTATION_TRANSPOSE.get(orientation)
     if transpose is not None:
         quantized = quantized.transpose(transpose)
@@ -190,3 +198,52 @@ def render_frame(source: Image.Image, faces: list[dict] | None = None,
             i += 1
 
     return bytes(out)
+
+
+def render_placeholder(lines: list[str], qr_url: str | None = None,
+                       orientation: str = "landscape") -> bytes:
+    """A readable full-panel message (plus an optional QR code) in the
+    same packed format as render_frame -- what /frame/image serves for a
+    frame that isn't claimed or configured yet, so a fresh device shows
+    instructions instead of an error screen and never error-loops."""
+    from PIL import ImageDraw, ImageFont
+
+    logical_w, logical_h = logical_render_size(orientation)
+    img = Image.new("RGB", (logical_w, logical_h), (255, 255, 255))
+    draw = ImageDraw.Draw(img)
+
+    title_font = ImageFont.load_default(size=34)
+    body_font = ImageFont.load_default(size=24)
+
+    qr_img = None
+    if qr_url:
+        import qrcode
+
+        qr = qrcode.QRCode(border=1, box_size=1)
+        qr.add_data(qr_url)
+        qr.make(fit=True)
+        raw = qr.make_image().get_image().convert("RGB")
+        # Integer upscale with NEAREST keeps modules crisp on the panel.
+        target = 220
+        scale = max(1, target // raw.width)
+        qr_img = raw.resize((raw.width * scale, raw.height * scale), Image.NEAREST)
+
+    # Vertical layout: text block, then QR under it, centered as a group.
+    line_heights = []
+    for i, line in enumerate(lines):
+        font = title_font if i == 0 else body_font
+        bbox = draw.textbbox((0, 0), line, font=font)
+        line_heights.append((line, font, bbox[2] - bbox[0], bbox[3] - bbox[1]))
+    gap = 14
+    text_h = sum(h for _, _, _, h in line_heights) + gap * (len(line_heights) - 1 if line_heights else 0)
+    total_h = text_h + (qr_img.height + 28 if qr_img else 0)
+    y = max(20, (logical_h - total_h) // 2)
+
+    for line, font, w, h in line_heights:
+        draw.text(((logical_w - w) // 2, y), line, fill=(0, 0, 0), font=font)
+        y += h + gap
+
+    if qr_img:
+        img.paste(qr_img, ((logical_w - qr_img.width) // 2, y + 14))
+
+    return _quantize_and_pack(img, orientation)

server/app/main.py

@@ -15,9 +15,10 @@ from fastapi import FastAPI, Request
 from fastapi.responses import HTMLResponse, RedirectResponse
 from fastapi.templating import Jinja2Templates
 
+from sqlalchemy import select
+
 from . import migration
 from .auth import (
-    MANAGEMENT_TOKEN_COOKIE,
     browser_token_valid,
     current_session,
     current_user,
@@ -25,8 +26,9 @@ from .auth import (
     users_exist,
 )
 from .db import SessionLocal
+from .models import Frame
 from .quiet_hours import ALL_TIMEZONES
-from .routers import api, device, pages
+from .routers import api, device, manage, pages
 from .routers.common import default_frame, immich_creds
 
 logger = logging.getLogger(__name__)
@@ -40,6 +42,30 @@ templates = Jinja2Templates(directory="app/templates")
 app.include_router(device.router)
 app.include_router(api.router)
 app.include_router(pages.router)
+app.include_router(manage.router)
+
+
+def _device_credential_redirect(request: Request, db, allow_legacy: bool) -> str | None:
+    """The on-frame manage QR points at the server root with the device's
+    own credentials (new firmware: ?id=&token=; deployed firmware:
+    ?token=<legacy shared token>). Those scans get the frame's limited
+    manage page -- never the full UI, which now requires a login.
+    allow_legacy is False before /setup has run: at that point a bare
+    ?token= hit is the admin coming through the token prompt to do
+    first-run setup, not a QR scan."""
+    device_id = request.query_params.get("id", "").strip().lower()
+    token = request.query_params.get("token", "")
+    if device_id and token:
+        frame = db.scalars(select(Frame).where(Frame.device_id == device_id)).first()
+        if frame is not None and token == frame.device_token:
+            return f"/m/{frame.manage_token}"
+    if allow_legacy and token and management_token() and token == management_token():
+        frame = db.scalars(
+            select(Frame).where(Frame.legacy_token_enabled == True)  # noqa: E712
+        ).first()
+        if frame is not None:
+            return f"/m/{frame.manage_token}"
+    return None
 
 
 @app.get("/health")
@@ -50,30 +76,34 @@ def health() -> dict:
 @app.get("/", response_class=HTMLResponse)
 def index(request: Request):
     """The web UI (still the single-frame page until Phase D). Access:
-    a user session (normal path once /setup has run), the legacy shared
-    token (the deployed frame's manage QR embeds ?token= -- kept working
-    until Phase C replaces it with the limited manage page), or -- only
-    while no users exist AND no token is configured -- fully open, the
-    original trusted-LAN default."""
+    a user session (the normal path once /setup has run), or -- only
+    while no users exist AND no MANAGEMENT_TOKEN is configured -- fully
+    open, the original trusted-LAN default. A hit carrying device
+    credentials (the on-frame manage QR) redirects to that frame's
+    limited manage page instead."""
     with SessionLocal() as db:
+        have_users = users_exist(db)
+        manage_redirect = _device_credential_redirect(request, db, allow_legacy=have_users)
+        if manage_redirect is not None:
+            return RedirectResponse(manage_redirect, status_code=303)
+
         user = current_user(request, db)
         session = current_session(request, db) if user else None
-        legacy_ok = browser_token_valid(request)
 
-        if user is None and not legacy_ok:
-            if not users_exist(db):
-                if management_token():
+        if user is None:
+            if not have_users:
+                if management_token() and not browser_token_valid(request):
                     supplied = request.query_params.get("token")
                     return templates.TemplateResponse(
                         "token_prompt.html", {"request": request, "wrong": supplied is not None}
                     )
-                # Fresh install, nothing configured: open, but nudge setup.
+                # Pre-setup: reachable (optionally token-gated), nudge setup.
                 return RedirectResponse("/setup", status_code=303)
             return RedirectResponse("/login", status_code=303)
 
         frame = default_frame(db)
         immich_url, _ = immich_creds(frame)
-        response = templates.TemplateResponse(
+        return templates.TemplateResponse(
             "index.html",
             {
                 "request": request,
@@ -84,13 +114,3 @@ def index(request: Request):
                 "csrf_token": session.csrf_token if session else None,
             },
         )
-
-    supplied = request.query_params.get("token")
-    if management_token() and supplied == management_token():
-        # Query-param access (typically the manage-menu QR code) earns a
-        # cookie so the rest of this visit's fetch()/<img> calls -- which
-        # never carry the query string -- stay authorized too.
-        response.set_cookie(
-            MANAGEMENT_TOKEN_COOKIE, supplied, max_age=86400 * 365, httponly=True, samesite="lax"
-        )
-    return response

server/app/routers/device.py

@@ -22,12 +22,14 @@ from ..auth import require_device
 from ..db import frame_locked, get_db
 from ..face_labels import compute_face_labels
 from ..firmware import firmware_path
+from ..image_pipeline import render_placeholder
 from ..models import BatteryLog, Frame
 from .common import (
     BATTERY_HISTORY_MAX,
     BATTERY_LOG_MAX,
     RECHARGE_JUMP_PCT,
     immich_client_for,
+    immich_creds,
     list_assets,
     render_asset,
     require_configured,
@@ -38,10 +40,43 @@ logger = logging.getLogger(__name__)
 router = APIRouter()
 
 
+def _setup_placeholder(frame: Frame, request: Request) -> bytes:
+    """What an unclaimed or not-yet-configured frame displays instead of a
+    photo -- instructions with a QR, rendered at 200 so the device treats
+    it as a perfectly normal image and never error-loops. The URLs are
+    built from the request's own base URL: whatever address the device
+    reached us at is by definition an address that works on this
+    network."""
+    base = str(request.base_url).rstrip("/")
+    if frame.owner_user_id is None and frame.device_id:
+        claim_url = f"{base}/claim?device_id={frame.device_id}"
+        return render_placeholder(
+            ["This frame isn't claimed yet", "Scan to link it to your account:"],
+            qr_url=claim_url,
+            orientation=frame.orientation,
+        )
+    if frame.owner_user_id is None:
+        return render_placeholder(
+            ["Almost there!", f"Open {base} to finish setting up this frame."],
+            orientation=frame.orientation,
+        )
+    return render_placeholder(
+        ["Almost there!", "Pick an album for this frame:", base],
+        qr_url=base,
+        orientation=frame.orientation,
+    )
+
+
+def _frame_configured(frame: Frame) -> bool:
+    url, key = immich_creds(frame)
+    return bool(url and key and frame.album_id)
+
+
 # Renderer dispatch seam for future frame modes (calendar, canva, ...):
 # /frame/image looks up the frame's mode here. Only photos exists today.
-def _render_photos_mode(db: Session, frame: Frame) -> bytes:
-    require_configured(frame)
+def _render_photos_mode(db: Session, frame: Frame, request: Request) -> bytes:
+    if not _frame_configured(frame):
+        return _setup_placeholder(frame, request)
     client = immich_client_for(frame)
     assets = list_assets(client, frame)
 
@@ -93,14 +128,18 @@ def frame_config(request: Request, frame: Frame = Depends(require_device), db: S
 
 
 @router.get("/frame/image")
-def frame_image(frame: Frame = Depends(require_device), db: Session = Depends(get_db)):
+def frame_image(
+    request: Request, frame: Frame = Depends(require_device), db: Session = Depends(get_db)
+):
     """Returns the frame's current image. For photos mode: idempotent --
     only actually advances to the next photo once refresh_interval_s has
     elapsed since the current one was set (see app/photo_queue.py) --
     safe to call as often as the device wants, including after an
-    unplanned reboot, without skipping ahead in the album."""
+    unplanned reboot, without skipping ahead in the album. An unclaimed/
+    unconfigured frame gets a rendered instruction placeholder (200, not
+    an error) so a fresh device never error-loops."""
     renderer = RENDERERS.get(frame.mode, _render_photos_mode)
-    return Response(content=renderer(db, frame), media_type="application/octet-stream")
+    return Response(content=renderer(db, frame, request), media_type="application/octet-stream")
 
 
 @router.post("/frame/advance")

server/app/routers/manage.py

@@ -0,0 +1,119 @@
+"""The limited no-login manage surface behind the on-frame "scan to
+manage" QR. The QR resolves to /m/<manage_token> (see main.index's
+device-credential redirect); the token grants exactly: view the current
+photo + upcoming queue, promote ("show next"), advance, back, and
+thumbnails. No settings, no removal, no other frames -- full control
+requires logging in."""
+
+from __future__ import annotations
+
+import logging
+
+import httpx
+from fastapi import APIRouter, Depends, HTTPException, Request
+from fastapi.responses import HTMLResponse, Response
+from fastapi.templating import Jinja2Templates
+from pydantic import BaseModel
+from sqlalchemy import select
+from sqlalchemy.orm import Session
+
+from .. import photo_queue, quiet_hours
+from ..db import frame_locked, get_db
+from ..models import Frame
+from .common import immich_client_for, list_assets, require_configured
+
+logger = logging.getLogger(__name__)
+
+router = APIRouter()
+templates = Jinja2Templates(directory="app/templates")
+
+
+def require_manage(manage_token: str, db: Session = Depends(get_db)) -> Frame:
+    frame = db.scalars(select(Frame).where(Frame.manage_token == manage_token)).first()
+    if frame is None:
+        raise HTTPException(404, "Unknown manage link")
+    return frame
+
+
+@router.get("/m/{manage_token}", response_class=HTMLResponse)
+def manage_page(manage_token: str, request: Request, db: Session = Depends(get_db)):
+    frame = require_manage(manage_token, db)
+    return templates.TemplateResponse(
+        "manage.html",
+        {"request": request, "frame": frame, "manage_token": manage_token},
+    )
+
+
+@router.get("/api/m/{manage_token}/queue")
+def manage_queue(frame: Frame = Depends(require_manage), db: Session = Depends(get_db)):
+    require_configured(frame)
+    client = immich_client_for(frame)
+    assets = list_assets(client, frame)
+
+    with frame_locked(db, frame.id) as cfg:
+        photo_queue.get_current(cfg, assets, in_quiet_hours=quiet_hours.in_quiet_hours(cfg))
+        photo_queue.sync_queue_length(cfg, assets)
+        current = cfg.current_asset_id
+        queue = list(cfg.queue)
+
+    def entry(asset_id: str) -> dict:
+        return {"id": asset_id, "thumbnail_url": f"/api/m/{frame.manage_token}/thumbnail/{asset_id}"}
+
+    return {
+        "frame_name": frame.name,
+        "current": entry(current) if current else None,
+        "upcoming": [entry(asset_id) for asset_id in queue],
+    }
+
+
+class ManagePromoteRequest(BaseModel):
+    asset_id: str
+
+
+@router.post("/api/m/{manage_token}/promote")
+def manage_promote(
+    body: ManagePromoteRequest,
+    frame: Frame = Depends(require_manage),
+    db: Session = Depends(get_db),
+):
+    with frame_locked(db, frame.id) as cfg:
+        if body.asset_id not in cfg.queue:
+            raise HTTPException(400, "That photo is no longer in the upcoming queue")
+        cfg.queue = [body.asset_id] + [a for a in cfg.queue if a != body.asset_id]
+    return {"status": "saved"}
+
+
+@router.post("/api/m/{manage_token}/advance")
+def manage_advance(frame: Frame = Depends(require_manage), db: Session = Depends(get_db)):
+    """Advances the server-side current photo; the panel itself updates
+    on the device's next wake (or its next-photo button)."""
+    require_configured(frame)
+    client = immich_client_for(frame)
+    assets = list_assets(client, frame)
+    with frame_locked(db, frame.id) as cfg:
+        photo_queue.advance_forced(cfg, assets)
+    return {"status": "saved"}
+
+
+@router.post("/api/m/{manage_token}/back")
+def manage_back(frame: Frame = Depends(require_manage), db: Session = Depends(get_db)):
+    require_configured(frame)
+    client = immich_client_for(frame)
+    assets = list_assets(client, frame)
+    with frame_locked(db, frame.id) as cfg:
+        photo_queue.back_forced(cfg, assets)
+    return {"status": "saved"}
+
+
+@router.get("/api/m/{manage_token}/thumbnail/{asset_id}")
+def manage_thumbnail(asset_id: str, frame: Frame = Depends(require_manage)):
+    """Thumbnails scoped to what this frame is actually showing/queuing --
+    the manage token must not become a general Immich proxy."""
+    if asset_id != frame.current_asset_id and asset_id not in frame.queue:
+        raise HTTPException(404, "Not on this frame")
+    client = immich_client_for(frame)
+    try:
+        content, content_type = client.download_asset_thumbnail(asset_id)
+    except httpx.HTTPError as e:
+        raise HTTPException(502, f"Could not download thumbnail from Immich: {e}") from e
+    return Response(content=content, media_type=content_type)

server/app/routers/pages.py

@@ -30,7 +30,7 @@ from ..auth import (
     verify_password,
 )
 from ..db import get_db
-from ..models import Frame, User, UserFrame
+from ..models import Frame, PendingClaim, User, UserFrame
 
 logger = logging.getLogger(__name__)
 
@@ -39,6 +39,7 @@ templates = Jinja2Templates(directory="app/templates")
 
 USERNAME_MAX_LEN = 64
 PASSWORD_MIN_LEN = 8
+PENDING_CLAIM_TTL_S = 24 * 3600
 
 
 def _set_session_cookie(response, cookie_value: str) -> None:
@@ -129,13 +130,23 @@ def setup_submit(
     return response
 
 
+def _safe_next(next_url: str) -> str:
+    """Same-site relative paths only -- a login redirect target from a
+    query param must never become an open redirect."""
+    if next_url.startswith("/") and not next_url.startswith("//"):
+        return next_url
+    return "/"
+
+
 @router.get("/login", response_class=HTMLResponse)
-def login_page(request: Request, db: Session = Depends(get_db)):
+def login_page(request: Request, next: str = "", db: Session = Depends(get_db)):
     if not users_exist(db):
         return RedirectResponse("/setup", status_code=303)
     if current_user(request, db) is not None:
-        return RedirectResponse("/", status_code=303)
-    return templates.TemplateResponse("login.html", {"request": request, "error": None})
+        return RedirectResponse(_safe_next(next), status_code=303)
+    return templates.TemplateResponse(
+        "login.html", {"request": request, "error": None, "next": next}
+    )
 
 
 @router.post("/login")
@@ -143,6 +154,7 @@ def login_submit(
     request: Request,
     username: str = Form(...),
     password: str = Form(...),
+    next: str = Form(""),
     db: Session = Depends(get_db),
 ):
     user = db.scalars(
@@ -151,11 +163,11 @@ def login_submit(
     if user is None or not user.password_hash or not verify_password(password, user.password_hash):
         return templates.TemplateResponse(
             "login.html",
-            {"request": request, "error": "Wrong username or password."},
+            {"request": request, "error": "Wrong username or password.", "next": next},
             status_code=401,
         )
     cookie_value, _ = create_session(db, user)
-    response = RedirectResponse("/", status_code=303)
+    response = RedirectResponse(_safe_next(next), status_code=303)
     _set_session_cookie(response, cookie_value)
     return response
 
@@ -169,6 +181,151 @@ def logout(request: Request, csrf_token: str = Form(""), db: Session = Depends(g
     return response
 
 
+def _normalize_device_id(device_id: str) -> str:
+    device_id = device_id.strip().lower()
+    if len(device_id) != 12 or any(c not in "0123456789abcdef" for c in device_id):
+        raise HTTPException(400, "Invalid device id")
+    return device_id
+
+
+def _attempt_claim(db: Session, user: User, device_id: str) -> str:
+    """Claims the frame for `user` if it has registered, else records a
+    pending claim the frame's first check-in will attach (see
+    auth._register_frame). Returns "claimed" or "pending"."""
+    frame = db.scalars(select(Frame).where(Frame.device_id == device_id)).first()
+    now = time.time()
+    if frame is not None:
+        if frame.owner_user_id is not None:
+            raise HTTPException(409, "That frame is already claimed")
+        frame.owner_user_id = user.id
+        frame.claimed_at = now
+        if frame.controlled_by_user_id is None:
+            frame.controlled_by_user_id = user.id
+        if db.get(UserFrame, (user.id, frame.id)) is None:
+            db.add(UserFrame(user_id=user.id, frame_id=frame.id))
+        pending = db.get(PendingClaim, device_id)
+        if pending is not None:
+            db.delete(pending)
+        db.commit()
+        logger.info("User '%s' claimed frame #%d (%s)", user.username, frame.id, device_id)
+        return "claimed"
+
+    pending = db.get(PendingClaim, device_id)
+    if pending is None:
+        pending = PendingClaim(device_id=device_id, user_id=user.id, created_at=now,
+                               expires_at=now + PENDING_CLAIM_TTL_S)
+        db.add(pending)
+    else:
+        pending.user_id = user.id
+        pending.expires_at = now + PENDING_CLAIM_TTL_S
+    db.commit()
+    logger.info("User '%s' filed a pending claim for device %s", user.username, device_id)
+    return "pending"
+
+
+def _render_claim(request: Request, db: Session, device_id: str, error: str | None = None):
+    user = current_user(request, db)
+    session = current_session(request, db) if user else None
+    frame = db.scalars(select(Frame).where(Frame.device_id == device_id)).first()
+    if frame is None:
+        status = "unregistered"
+        pending = db.get(PendingClaim, device_id)
+        pending_yours = bool(pending and user and pending.user_id == user.id
+                             and pending.expires_at > time.time())
+    elif frame.owner_user_id is None:
+        status, pending_yours = "unclaimed", False
+    elif user is not None and (
+        frame.owner_user_id == user.id or db.get(UserFrame, (user.id, frame.id)) is not None
+    ):
+        status, pending_yours = "claimed_yours", False
+    else:
+        status, pending_yours = "claimed", False
+    return templates.TemplateResponse(
+        "claim.html",
+        {
+            "request": request,
+            "device_id": device_id,
+            "status": status,
+            "pending_yours": pending_yours,
+            "user": user,
+            "csrf_token": session.csrf_token if session else None,
+            "error": error,
+        },
+    )
+
+
+@router.get("/claim", response_class=HTMLResponse)
+def claim_page(request: Request, device_id: str = "", db: Session = Depends(get_db)):
+    """Where the captive portal's post-provisioning redirect lands. Also
+    the enrollment gate: a valid device id is what entitles a stranger to
+    create an account (signup form on this page); everyone else gets
+    enrolled by the admin."""
+    device_id = _normalize_device_id(device_id)
+    return _render_claim(request, db, device_id)
+
+
+@router.post("/claim")
+def claim_submit(
+    request: Request,
+    device_id: str = Form(...),
+    csrf_token: str = Form(""),
+    db: Session = Depends(get_db),
+):
+    device_id = _normalize_device_id(device_id)
+    user = current_user(request, db)
+    if user is None:
+        return RedirectResponse(f"/login?next=/claim%3Fdevice_id%3D{device_id}", status_code=303)
+    _check_form_csrf(request, db, csrf_token)
+    try:
+        _attempt_claim(db, user, device_id)
+    except HTTPException as e:
+        if e.status_code == 409:
+            return _render_claim(request, db, device_id, error=e.detail)
+        raise
+    return RedirectResponse(f"/claim?device_id={device_id}", status_code=303)
+
+
+@router.post("/claim/signup")
+def claim_signup(
+    request: Request,
+    device_id: str = Form(...),
+    username: str = Form(...),
+    password: str = Form(...),
+    db: Session = Depends(get_db),
+):
+    """Account creation, gated on a plausible frame claim: the device id
+    must belong to a frame that is unclaimed (or not yet registered --
+    the user beat the device here after provisioning). A fabricated id
+    can create an orphan account whose pending claim expires in 24h --
+    accepted at household scale, and visible in /admin."""
+    device_id = _normalize_device_id(device_id)
+    frame = db.scalars(select(Frame).where(Frame.device_id == device_id)).first()
+    if frame is not None and frame.owner_user_id is not None:
+        return _render_claim(request, db, device_id,
+                             error="That frame is already claimed -- log in instead.")
+    username = _validate_credentials(username, password)
+    if db.scalars(select(User).where(User.username == username)).first() is not None:
+        return _render_claim(request, db, device_id,
+                             error=f"Username '{username}' is taken -- log in instead?")
+
+    user = User(
+        username=username,
+        display_name=username,
+        password_hash=hash_password(password),
+        is_admin=False,
+        created_at=time.time(),
+    )
+    db.add(user)
+    db.commit()
+    logger.info("User '%s' signed up via claim gate for device %s", username, device_id)
+
+    _attempt_claim(db, user, device_id)
+    cookie_value, _ = create_session(db, user)
+    response = RedirectResponse(f"/claim?device_id={device_id}", status_code=303)
+    _set_session_cookie(response, cookie_value)
+    return response
+
+
 @router.get("/settings", response_class=HTMLResponse)
 def settings_page(request: Request, db: Session = Depends(get_db)):
     user = current_user(request, db)

server/app/templates/claim.html

@@ -0,0 +1,72 @@
+{% extends "base.html" %}
+
+{% block page_class %}page-narrow{% endblock %}
+
+{% block subtitle %}
+<p class="sub">Claim your frame</p>
+{% endblock %}
+
+{% block extra_head %}
+  {% if status == "unregistered" %}<meta http-equiv="refresh" content="6">{% endif %}
+{% endblock %}
+
+{% block content %}
+  {% if error %}<div class="status err">{{ error }}</div>{% endif %}
+
+  <section class="card">
+    <h2 class="card-title">Frame <code>{{ device_id }}</code></h2>
+
+    {% if status == "claimed_yours" %}
+      <div class="status ok">This frame is linked to your account.</div>
+      <p class="sub">It will show up in your frame list. If it was just
+        provisioned, give it a minute to connect and fetch its first image.</p>
+      <p><a href="/">Go to your frames</a></p>
+
+    {% elif status == "claimed" %}
+      <p class="sub">This frame already belongs to someone. If it's yours,
+        ask them (or an admin) to link your account to it.</p>
+
+    {% elif status == "unregistered" %}
+      {% if pending_yours %}
+        <div class="status ok">Claim recorded.</div>
+        <p class="sub">Waiting for the frame to connect for the first time --
+          it links to your account automatically the moment it checks in.
+          This page refreshes itself; it's safe to close, too.</p>
+      {% else %}
+        <p class="sub">The frame hasn't checked in yet -- it's probably still
+          restarting and joining your WiFi. This page refreshes itself.
+          {% if user %}You can claim it now anyway; it'll attach when it
+          arrives.{% endif %}</p>
+      {% endif %}
+    {% elif status == "unclaimed" %}
+      <p class="sub">This frame is connected and ready to be claimed.</p>
+    {% endif %}
+
+    {% if user and status in ("unclaimed", "unregistered") and not pending_yours %}
+      <form method="post" action="/claim">
+        <input type="hidden" name="device_id" value="{{ device_id }}">
+        <input type="hidden" name="csrf_token" value="{{ csrf_token }}">
+        <button type="submit">Claim this frame</button>
+      </form>
+    {% endif %}
+  </section>
+
+  {% if not user and status in ("unclaimed", "unregistered") %}
+    <section class="card">
+      <h2 class="card-title">Create your account</h2>
+      <p class="sub">A valid frame is your invitation -- set up an account to
+        claim it. Already have one?
+        <a href="/login?next=/claim%3Fdevice_id%3D{{ device_id }}">Log in instead</a>.</p>
+      <form method="post" action="/claim/signup">
+        <input type="hidden" name="device_id" value="{{ device_id }}">
+        <label>Username
+          <input type="text" name="username" maxlength="64" required autocomplete="username">
+        </label>
+        <label>Password
+          <input type="password" name="password" minlength="8" required autocomplete="new-password">
+        </label>
+        <button type="submit">Create account &amp; claim frame</button>
+      </form>
+    </section>
+  {% endif %}
+{% endblock %}

server/app/templates/login.html

@@ -11,6 +11,7 @@
     <h2 class="card-title">Log in</h2>
     {% if error %}<div class="status err">{{ error }}</div>{% endif %}
     <form method="post" action="/login">
+      <input type="hidden" name="next" value="{{ next }}">
       <label>Username
         <input type="text" name="username" maxlength="64" required autofocus autocomplete="username">
       </label>

server/app/templates/manage.html

@@ -0,0 +1,116 @@
+{% extends "base.html" %}
+
+{% block subtitle %}
+<p class="sub">{{ frame.name or "Frame" }} &mdash; quick controls</p>
+{% endblock %}
+
+{% block content %}
+  <div class="layout">
+    <div class="main-col">
+      <section class="card">
+        <h2 class="card-title">Up next</h2>
+        <p class="sub">Tap "Show next" to move a photo to the front. The frame
+          picks it up on its next refresh. <a href="/login">Log in</a> for full
+          settings.</p>
+        <div id="upcoming-grid" class="photo-grid"></div>
+      </section>
+    </div>
+    <div class="side-col">
+      <section class="card">
+        <h2 class="card-title">Now displaying</h2>
+        <div id="current-thumb"><p class="sub">Loading...</p></div>
+        <div style="display: flex; gap: 8px;">
+          <button type="button" class="secondary" id="btn-back">&larr; Previous</button>
+          <button type="button" class="secondary" id="btn-advance">Next &rarr;</button>
+        </div>
+        <p class="sub" style="margin-top: 8px;">Changes what the frame shows on
+          its next wake.</p>
+      </section>
+    </div>
+  </div>
+  <div id="result"></div>
+{% endblock %}
+
+{% block scripts %}
+  <script>
+    const TOKEN = {{ manage_token | tojson }};
+    const resultEl = document.getElementById('result');
+
+    function showStatus(ok, message) {
+      resultEl.innerHTML = `<div class="status ${ok ? 'ok' : 'err'}">${message}</div>`;
+    }
+
+    async function post(path, body) {
+      const resp = await fetch(`/api/m/${TOKEN}/${path}`, {
+        method: 'POST',
+        headers: body ? { 'Content-Type': 'application/json' } : {},
+        body: body ? JSON.stringify(body) : undefined,
+      });
+      if (!resp.ok) {
+        throw new Error(await resp.text());
+      }
+    }
+
+    async function loadQueue() {
+      const currentEl = document.getElementById('current-thumb');
+      const grid = document.getElementById('upcoming-grid');
+      try {
+        const resp = await fetch(`/api/m/${TOKEN}/queue`);
+        if (!resp.ok) {
+          currentEl.innerHTML = '<p class="sub">This frame isn\'t set up yet.</p>';
+          return;
+        }
+        const data = await resp.json();
+        currentEl.innerHTML = '';
+        if (data.current) {
+          const img = document.createElement('img');
+          img.className = 'thumb';
+          img.src = data.current.thumbnail_url;
+          img.alt = '';
+          currentEl.appendChild(img);
+        } else {
+          currentEl.innerHTML = '<p class="sub">Nothing displayed yet.</p>';
+        }
+        grid.innerHTML = '';
+        for (const item of data.upcoming) {
+          const card = document.createElement('div');
+          card.className = 'photo-card';
+          const img = document.createElement('img');
+          img.src = item.thumbnail_url;
+          img.alt = '';
+          img.draggable = false;
+          card.appendChild(img);
+          const btn = document.createElement('button');
+          btn.type = 'button';
+          btn.className = 'show-next';
+          btn.textContent = 'Show next';
+          btn.addEventListener('click', async () => {
+            try {
+              await post('promote', { asset_id: item.id });
+              showStatus(true, 'Moved to the front.');
+              loadQueue();
+            } catch (e) {
+              showStatus(false, e.message);
+            }
+          });
+          card.appendChild(btn);
+          grid.appendChild(card);
+        }
+      } catch (e) {
+        currentEl.innerHTML = '<p class="sub">Could not load.</p>';
+      }
+    }
+
+    document.getElementById('btn-advance').addEventListener('click', async () => {
+      try { await post('advance'); showStatus(true, 'Advanced.'); loadQueue(); }
+      catch (e) { showStatus(false, e.message); }
+    });
+    document.getElementById('btn-back').addEventListener('click', async () => {
+      try { await post('back'); showStatus(true, 'Went back.'); loadQueue(); }
+      catch (e) { showStatus(false, e.message); }
+    });
+
+    loadQueue();
+    setInterval(loadQueue, 15000);
+  </script>
+{% endblock %}

server/requirements.txt

@@ -6,3 +6,4 @@ pillow==12.3.0
 python-multipart==0.0.20
 jinja2==3.1.5
 sqlalchemy==2.0.51
+qrcode==8.2