Add a static image widget (PNG/JPEG/GIF/BMP/WEBP/TIFF/PDF upload)

A new widget type showing a single user-uploaded image with no live
upstream to poll -- decoded once at upload time (PDF's first page via
pypdfium2, BSD-3-Clause/Apache-2.0, no copyleft exposure) into plain RGB
PNG bytes, then composed per a crop/stretch/letterbox display mode like
the photos widget.

server/app/routers/api_widgets.py

@@ -19,7 +19,7 @@ import io
 import time
 
 import httpx
-from fastapi import APIRouter, Depends, Form, HTTPException, Request
+from fastapi import APIRouter, Depends, File, Form, HTTPException, Request, UploadFile
 from fastapi.responses import Response
 from PIL import Image
 from pydantic import BaseModel
@@ -29,13 +29,21 @@ from sqlalchemy.orm import Session
 from .. import calendar_render, grid, photo_queue, quiet_hours, weather, webdav_client
 from ..auth import require_frame_control, require_frame_view, require_user_api
 from ..db import frame_locked, get_db, widget_locked
-from ..image_pipeline import DEFAULT_DISPLAY_MODE, DISPLAY_MODES, render_preview_png
+from ..image_pipeline import (
+    DEFAULT_DISPLAY_MODE,
+    DEFAULT_STATIC_DISPLAY_MODE,
+    DISPLAY_MODES,
+    STATIC_DISPLAY_MODES,
+    render_preview_png,
+)
+from ..image_upload import decode_upload
 from ..models import (
     CalendarWidgetConfig,
     Frame,
     FrameCalendar,
     FrameTaskList,
     PhotoWidgetConfig,
+    StaticWidgetConfig,
     TaskWidgetConfig,
     WhiteboardWidgetConfig,
     WIDGET_CONFIG_MODELS,
@@ -245,7 +253,9 @@ def api_widgets_clear(frame: Frame = Depends(require_frame_control), db: Session
 def api_widget_config_save(
     frame_widget: tuple[Frame, Widget] = Depends(require_widget_control),
     db: Session = Depends(get_db),
-    # photos
+    # photos (display_mode is also reused by the static branch below --
+    # each widget's own dialog only ever posts its own fields, so the two
+    # Form(None) uses of the same name never collide)
     album_id: str | None = Form(None),
     order: str | None = Form(None),
     display_mode: str | None = Form(None),
@@ -333,6 +343,10 @@ def api_widget_config_save(
             if tasks_show_completed is not None and tasks_show_completed != tcfg.show_completed:
                 tcfg.show_completed = tasks_show_completed
                 tcfg.checked_at = 0.0  # pick up the change promptly
+    elif widget.widget_type == "static":
+        with widget_locked(db, frame.id, widget.id) as (_, _, scfg):
+            if display_mode is not None:
+                scfg.display_mode = display_mode if display_mode in STATIC_DISPLAY_MODES else DEFAULT_STATIC_DISPLAY_MODE
     with frame_locked(db, frame.id) as cfg:
         cfg.stats_config_saves += 1
     return {"status": "saved"}
@@ -787,6 +801,57 @@ def api_widget_weather_city_remove(
     return {"status": "saved"}
 
 
+# --- Static image: upload/preview -----------------------------------------
+
+@router.post("/api/frames/{frame_id}/widgets/{widget_id}/static-upload")
+async def api_widget_static_upload(
+    file: UploadFile = File(...),
+    frame_widget: tuple[Frame, Widget] = Depends(require_widget_control),
+    db: Session = Depends(get_db),
+):
+    """Decodes an uploaded PNG/JPEG/GIF/BMP/WEBP/TIFF/PDF (see
+    app/image_upload.py) into plain RGB PNG bytes and stores it as this
+    widget's whole content -- a widget-wide setting like a photos
+    widget's album, hence require_widget_control (the frame's "take
+    control" gate) rather than the calendar/tasks owner-adds/anyone-mutes
+    split, since there's only ever one image and no per-person data."""
+    frame, widget = frame_widget
+    _require_widget_type(widget, "static")
+    data = await file.read()
+    if not data:
+        raise HTTPException(400, "No file uploaded")
+    image = decode_upload(data)
+    buf = io.BytesIO()
+    image.save(buf, format="PNG")
+    with widget_locked(db, frame.id, widget.id) as (_, _, scfg):
+        scfg.image = buf.getvalue()
+        scfg.original_filename = (file.filename or "")[:255]
+        scfg.uploaded_at = time.time()
+    return {"status": "saved", "filename": scfg.original_filename}
+
+
+@router.get("/api/frames/{frame_id}/widgets/{widget_id}/preview/static")
+def api_widget_preview_static(
+    frame_widget: tuple[Frame, Widget] = Depends(require_widget_view), db: Session = Depends(get_db)
+):
+    """The uploaded image run through this frame's actual saved
+    rendering pipeline (display mode, palette, color/contrast/dithering)
+    -- "how it will look on the frame", same convention as the photos/
+    whiteboard preview endpoints."""
+    frame, widget = frame_widget
+    _require_widget_type(widget, "static")
+    scfg = db.get(StaticWidgetConfig, widget.id)
+    if not scfg.image:
+        raise HTTPException(400, "No image uploaded to this widget yet")
+    source = Image.open(io.BytesIO(scfg.image)).convert("RGB")
+    png = render_preview_png(
+        source, faces=None, orientation=frame.orientation, palette_rgb=frame.palette_rgb,
+        display_mode=scfg.display_mode, color_boost=frame.color_boost,
+        contrast_boost=frame.contrast_boost, dither_strength=frame.dither_strength,
+    )
+    return Response(content=png, media_type="image/png")
+
+
 # --- Whiteboard: source/preview ------------------------------------------
 
 class WhiteboardSourceRequest(BaseModel):