Add calendar frame mode + server-side manage overlay (server)

calendar_feed.py/calendar_render.py: fetch/merge per-user ICS feeds,
render agenda/week/month views. manage_overlay.py: composites the
manage-button overlay server-side (QR, battery, location/date,
share-QR, face labels), reused by every render mode. device.py/common.py
wire both together: mode dispatch for /frame/image+advance+back, and
the &manage=1 flag. Plus UI (frame_config.html Calendar card, settings
calendar URL field) and the icalendar/recurring-ical-events deps.

server/app/face_labels.py

@@ -1,6 +1,6 @@
 """Maps named faces (from Immich's own face recognition/People feature)
-onto their position in the final rendered 800x480 frame, for the
-manage-button overlay's escalated "who's in this photo" menu level.
+onto their position in the final rendered frame, for the manage-button
+overlay's named-face labels (see manage_overlay.py, which draws them).
 
 No face detection or recognition happens here or anywhere else in this
 project -- Immich's GET /api/faces?id={assetId} already returns each
@@ -15,32 +15,32 @@ import io
 
 from PIL import Image, ImageOps
 
-from .image_pipeline import _has_bounding_box, _placement_transform, logical_render_size, logical_to_native
+from .image_pipeline import _has_bounding_box, _placement_transform, logical_render_size
 
-# Small caps, not arbitrary: each label is its own malloc'd overlay
-# buffer on the device (see firmware/main/manage_qr_overlay.c), and the
-# four existing fixed corner regions already use a meaningful chunk of
-# the ESP32-C6's limited RAM. Capping at 4 short names keeps the total
-# overlay memory budget well clear of the WiFi/HTTP stack's own needs.
-MAX_LABELED_FACES = 4
-NAME_MAX_LEN = 10
+# Not a memory constraint anymore (the overlay renders server-side now,
+# not malloc'd per-label on the device) -- purely a legibility cap. A
+# photo with a dozen named people would just be visual clutter regardless
+# of what's rendering it.
+MAX_LABELED_FACES = 6
 
 
 def compute_face_labels(preview_bytes: bytes, faces: list[dict], display_mode: str,
                         orientation: str = "landscape") -> list[dict]:
-    """Returns up to MAX_LABELED_FACES [{"name", "x", "y"}], x/y in native
-    800x480 panel pixel space at each named face's bottom-center point.
+    """Returns up to MAX_LABELED_FACES [{"name", "x", "y"}], x/y in
+    logical (pre-rotation) frame space at each named face's bottom-center
+    point -- manage_overlay.compose() draws these directly onto the
+    logical-space image before it's rotated into native panel space, so
+    no rotation happens here (contrast with the old firmware-side
+    version, which drew post-rotation and needed logical_to_native).
     Faces without an Immich-identified person name are skipped entirely.
     preview_bytes must be the same preview image render_frame() used for
     the currently-displayed frame, and display_mode/orientation must
     match the settings that were active then -- otherwise the placement
-    and rotation computed here won't match what's actually on screen.
+    computed here won't match what's actually on screen.
 
-    The placement math runs in logical (pre-rotation) space, matching
-    render_frame()'s composition step (see image_pipeline._placement_transform,
-    shared so the two can't drift apart); each anchor is then rotated
-    into native panel coordinates via logical_to_native(), since the
-    firmware draws labels in native space.
+    The placement math matches render_frame()'s own composition step
+    exactly (see image_pipeline._placement_transform, shared so the two
+    can't drift apart).
     """
     named = [face for face in faces if (face.get("person") or {}).get("name")]
     if not named:
@@ -71,11 +71,6 @@ def compute_face_labels(preview_bytes: bytes, faces: list[dict], display_mode: s
         if not (0 <= frame_x <= logical_w and 0 <= frame_y <= logical_h):
             continue  # this face got cropped out of the final frame entirely
 
-        name = face["person"]["name"]
-        if len(name) > NAME_MAX_LEN:
-            name = name[: NAME_MAX_LEN - 3] + "..."
-
-        native_x, native_y = logical_to_native(frame_x, frame_y, orientation)
-        labels.append({"name": name, "x": native_x, "y": native_y})
+        labels.append({"name": face["person"]["name"], "x": int(frame_x), "y": int(frame_y)})
 
     return labels