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>

CalendarrWidgets/CalendarDayWidgetView.swift

@@ -41,11 +41,11 @@ struct CalendarDayWidgetView: View {
             VStack(alignment: .leading, spacing: 0) {
                 header(primary: primary)
                 weekStrip(snapshot: s, primary: primary, accent: accent)
-                    .padding(.vertical, 5)
+                    .padding(.vertical, 3)
                 Rectangle()
                     .fill(Color(widgetHex: s.lineColorHex).opacity(0.4))
                     .frame(height: 0.5)
-                    .padding(.bottom, 6)
+                    .padding(.bottom, 4)
                 eventList(accent: accent)
             }
         } else {
@@ -61,9 +61,9 @@ struct CalendarDayWidgetView: View {
     private func header(primary: Color) -> some View {
         HStack(alignment: .top, spacing: 6) {
             Text("\(cal.component(.day, from: entry.date))")
-                .font(.system(size: 36, weight: .bold))
+                .font(.system(size: 30, weight: .bold))
                 .foregroundStyle(primary)
-                .frame(width: 44, alignment: .leading)
+                .frame(width: 40, alignment: .leading)
                 .minimumScaleFactor(0.7)
             VStack(alignment: .leading, spacing: 1) {
                 Text(monthFmt.string(from: entry.date).uppercased())
@@ -125,12 +125,12 @@ struct CalendarDayWidgetView: View {
                 .foregroundStyle(.secondary)
             Spacer(minLength: 0)
         } else {
-            VStack(alignment: .leading, spacing: 5) {
+            VStack(alignment: .leading, spacing: 4) {
                 ForEach(upcomingEvents.prefix(3)) { ev in
                     HStack(alignment: .center, spacing: 6) {
                         RoundedRectangle(cornerRadius: 1.5)
                             .fill(Color(widgetHex: ev.colorHex))
-                            .frame(width: 3, height: 26)
+                            .frame(width: 3, height: 22)
                         VStack(alignment: .leading, spacing: 1) {
                             Text(ev.title)
                                 .font(.system(size: 11, weight: .semibold))