Add weather to calendar mode; fix CalDAV events never showing

Weather: multiple cities per frame, geocoded via Open-Meteo (no API
key), shown above the event list on agenda/today & tomorrow/week views
-- never month, no room for it there. Hand-drawn sun/cloud/rain/snow/
thunderstorm icons (no new font/icon asset, same primitives-only
approach the rest of calendar_render.py already uses). City geocoding
handles "City, State" qualifiers Open-Meteo's own search doesn't
(disambiguates same-named cities, e.g. the three "Portland"s).

CalDAV fix: events were never showing despite calendars discovering
fine, because fetch_calendar_events relied on the calendar-query
REPORT's server-side time-range filter, which real servers implement
inconsistently (confirmed against a real server, not just guessed --
reproduced locally with Radicale). Switched to fetching every event
unfiltered and doing all date-window filtering/expansion client-side,
same approach already used for plain ICS feeds.

server/app/models.py

@@ -187,6 +187,21 @@ class Frame(Base):
     # outage to everyone who looks at it.
     calendar_fetch_summary: Mapped[str] = mapped_column(String, default="")
 
+    # Optional weather strip, agenda/today & tomorrow/week views only --
+    # never month, there's no room (see calendar_render.py's _BUILDERS).
+    # Off by default.
+    calendar_weather_enabled: Mapped[bool] = mapped_column(Boolean, default=False)
+    calendar_weather_units: Mapped[str] = mapped_column(String, default="fahrenheit")  # "fahrenheit" | "celsius"
+    # [{"label", "latitude", "longitude"}, ...] -- each geocoded once via
+    # weather.geocode_city() when added from the Calendar tab.
+    calendar_weather_cities: Mapped[list | None] = mapped_column(JSON, nullable=True, default=None)
+    # Throttled per-city forecast cache (see routers/common.py's
+    # get_or_refresh_weather) -- same shape idiom as
+    # calendar_checked_at/calendar_cached_events above.
+    # [{"label", "days": {"YYYY-MM-DD": {"code","high","low"}}}, ...]
+    calendar_weather_checked_at: Mapped[float] = mapped_column(Float, default=0.0)
+    calendar_weather_cached: Mapped[list | None] = mapped_column(JSON, nullable=True, default=None)
+
     # -- state --
     current_asset_id: Mapped[str] = mapped_column(String, default="")
     current_asset_set_at: Mapped[float] = mapped_column(Float, default=0.0)