fix(reminders): suppress notifications for disabled calendars

Reminders fired for every due CalendarAlerts row regardless of whether
the event's calendar had been disabled in-app, even though disabled
calendars are hidden from every other surface. Carry the calendar id
through the alert and filter disabled calendars before posting, while
still marking all due alerts fired so the provider stops re-broadcasting
the suppressed ones.

Closes #17

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

CHANGELOG.md

@@ -16,6 +16,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   turn reminders off entirely. Thanks to @moonj for the suggestion ([#14]).
 
 ### Fixed
+- Disabled calendars no longer notify. Reminders for events in a calendar you
+  have disabled (Settings → Calendars) are now suppressed instead of still
+  popping up — matching how a disabled calendar's events already stay hidden
+  everywhere else in the app ([#17]).
 - Editing a single occurrence of a recurring event works again. Choosing **Only
   this event** and saving a change to one event in a repeating series silently
   did nothing — the change was rejected and the edit form simply reappeared with
@@ -749,3 +753,4 @@ automatically, with zero telemetry and no internet permission.
 [#13]: https://codeberg.org/jlmakiola/calendula/issues/13
 [#14]: https://codeberg.org/jlmakiola/calendula/issues/14
 [#16]: https://codeberg.org/jlmakiola/calendula/issues/16
+[#17]: https://codeberg.org/jlmakiola/calendula/issues/17