feat: HA/Google edit, full-page event detail, KW+zigzag divider, HSV picker, splash

- Home Assistant & Google events now editable/deletable (server PUT/DELETE
  endpoints wired; saveEvent had no HA/Google update branch -> created dupes)
- Event detail is now a full screen (Scaffold) instead of a bottom sheet:
  long notes scroll, action buttons no longer hidden behind the system nav bar;
  distinct calendar vs notes icons
- Month view: calendar-week number on Mondays, month-boundary divider with
  zigzag step (month_divider_color), month label in month_label_color,
  text/line contrast applied
- Compact top bar with smaller title; prev/next chevrons present in month view
  and scroll one month at a time
- Real HSV colour picker (SV field + hue slider + hex) for primary, accent,
  today, month-divider and month-label colours
- Black status/navigation bars; portrait-locked; crisp custom splash with app
  name, high-res icon and © Scarriffle

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

app/src/main/java/com/scarriffle/calendarr/ui/L10n.kt

@@ -95,6 +95,7 @@ object L10n {
             "event.color" to "Terminfarbe", "event.reset_color" to "Zurücksetzen",
             "event.edit_title" to "Termin bearbeiten", "event.new_title" to "Neuer Termin",
             "event.copy_title" to "Termin kopieren", "event.copy_to" to "In Kalender kopieren",
+            "event.detail_title" to "Termin", "event.source" to "Quelle",
             "event.save" to "Sichern", "event.add" to "Hinzufügen",
             "event.delete_confirm" to "Diesen Termin löschen?",
             "accounts.title" to "Konten", "accounts.loading" to "Lade Konten…",
@@ -195,6 +196,7 @@ object L10n {
             "event.color" to "Event color", "event.reset_color" to "Reset",
             "event.edit_title" to "Edit event", "event.new_title" to "New event",
             "event.copy_title" to "Copy event", "event.copy_to" to "Copy to calendar",
+            "event.detail_title" to "Event", "event.source" to "Source",
             "event.save" to "Save", "event.add" to "Add",
             "event.delete_confirm" to "Delete this event?",
             "accounts.title" to "Accounts", "accounts.loading" to "Loading accounts…",