Week view: relative start-day offset for non-7-day counts; hide week-only settings elsewhere

calendar_week_start's fixed-weekday anchor ("start on the most recent
Monday") stops making sense once the view isn't a literal calendar
week, so a non-7-day week view now starts calendar_week_start_offset
days from today instead (0 = starts today, negative/positive = past/
future) -- calendar_week_start still governs at the default 7 days,
unchanged.

Also hides the Calendar tab's week-only fields (days to show, layout,
start offset) unless View is actually set to Week, and further hides
the new start-offset field specifically when Days to show is 7 (where
it has no effect). "Week starts on" stays visible for Month too, since
it actually still applies there.

server/app/routers/api_frames.py

@@ -104,6 +104,7 @@ def api_config_save(
     calendar_week_start: int | None = Form(None),
     calendar_week_days: int | None = Form(None),
     calendar_week_layout: str | None = Form(None),
+    calendar_week_start_offset: int | None = Form(None),
     calendar_weather_enabled: bool | None = Form(None),
     calendar_weather_units: str | None = Form(None),
     calendar_tasks_enabled: bool | None = Form(None),
@@ -194,6 +195,11 @@ def api_config_save(
             cfg.calendar_week_days = new_days
         if calendar_week_layout is not None:
             cfg.calendar_week_layout = calendar_week_layout if calendar_week_layout in ("horizontal", "vertical") else "horizontal"
+        if calendar_week_start_offset is not None:
+            new_offset = max(-30, min(30, calendar_week_start_offset))
+            if new_offset != cfg.calendar_week_start_offset:
+                cfg.calendar_browse_offset = 0
+            cfg.calendar_week_start_offset = new_offset
         if calendar_weather_enabled is not None:
             cfg.calendar_weather_enabled = calendar_weather_enabled
         if calendar_weather_units is not None and calendar_weather_units in ("fahrenheit", "celsius"):
@@ -571,6 +577,7 @@ def api_preview_calendar(frame: Frame = Depends(require_frame_view), db: Session
         week_start=frame.calendar_week_start,
         weather_cities=weather_cities, weather_units=frame.calendar_weather_units,
         week_days=frame.calendar_week_days, week_layout=frame.calendar_week_layout, tasks=tasks,
+        week_start_offset=frame.calendar_week_start_offset,
     )
     return Response(content=png, media_type="image/png")
 

server/app/routers/device.py

@@ -149,6 +149,7 @@ def _render_calendar_mode(db: Session, frame: Frame, request: Request, manage: d
         week_start = locked.calendar_week_start
         week_days = locked.calendar_week_days
         week_layout = locked.calendar_week_layout
+        week_start_offset = locked.calendar_week_start_offset
         inlay_wanted = locked.calendar_photo_inlay
 
     events, summary = get_or_refresh_calendar_events(db, frame)
@@ -183,7 +184,7 @@ def _render_calendar_mode(db: Session, frame: Frame, request: Request, manage: d
         palette_rgb=frame.palette_rgb, timezone=frame.timezone,
         photo_inlay=photo_inlay, fetch_summary=summary, manage=manage, week_start=week_start,
         weather_cities=weather_cities, weather_units=frame.calendar_weather_units,
-        week_days=week_days, week_layout=week_layout, tasks=tasks,
+        week_days=week_days, week_layout=week_layout, tasks=tasks, week_start_offset=week_start_offset,
     )