iOS: localization fixes, per-calendar reminders, widget polish

C1 — Localization: route the remaining hardcoded German strings through
L10n (LoginView, ServerSetupView, SettingsView email, EventDetailSheet) so
"System Default" + English device language shows fully English text.

C2 — Per-calendar reminders: parse the new reminders_enabled flag on every
calendar type; CalendarStore persists a reminderDisabledKeys set and passes
it to NotificationScheduler, which skips events of muted calendars (default
and per-event reminders). Filter sheet gains a per-calendar reminder toggle
(leading swipe + bell.slash indicator), reconciled from the server and
synced back via PUT.

C3 — Widgets:
- Shared WidgetTime.range helper; Today / Today & Tomorrow / Three Days /
  Up Next now show start–end instead of only the start time.
- This Week: show up to 6 events per day (was 3) to use the height.
- Two Weeks: mini event-title pills instead of bare dots.
- Two Months: weeks expand to fill the column (no more empty lower third).
- Day & Events: smaller header/strip/rows so content stops clipping.
- Next 5 days → Next 7 days (range + labels), higher row cap.

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

Calendarr iOS/Services/CalendarrAPI.swift

@@ -402,6 +402,21 @@ class CalendarrAPI {
                               body: ["enabled": !hidden, "sidebar_hidden": hidden])
     }
 
+    /// Toggle a calendar's server-side `reminders_enabled` flag. Supported for
+    /// all source types (caldav/google/homeassistant/local/ical).
+    func setCalendarRemindersEnabled(source: String, calendarId: Int, enabled: Bool) async throws {
+        let path: String
+        switch source {
+        case "caldav":        path = "/api/caldav/calendars/\(calendarId)"
+        case "google":        path = "/api/google/calendars/\(calendarId)"
+        case "homeassistant": path = "/api/homeassistant/calendars/\(calendarId)"
+        case "local":         path = "/api/local/calendars/\(calendarId)"
+        case "ical":          path = "/api/ical/subscriptions/\(calendarId)"
+        default:              return
+        }
+        _ = try await request(path, method: "PUT", body: ["reminders_enabled": enabled])
+    }
+
     // MARK: – Calendar colour
 
     func updateLocalCalendarColor(id: Int, color: String) async throws {