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/data/CalendarRepository.kt

@@ -305,31 +305,56 @@ class CalendarRepository @Inject constructor(
         calendarDbId: Int, title: String, start: Instant, end: Instant,
         isAllDay: Boolean, location: String, description: String,
     ) = guarded {
-        api.createGoogleEvent(
-            jsonBody(
-                "calendar_db_id" to calendarDbId, "title" to title,
-                "start" to Dates.format(start, isAllDay), "end" to Dates.format(end, isAllDay),
-                "allDay" to isAllDay, "location" to location, "description" to description,
-            )
-        ).ensureSuccess()
+        api.createGoogleEvent(simpleEventBody("calendar_db_id", calendarDbId, title, start, end, isAllDay, location, description))
+            .ensureSuccess()
     }
 
+    suspend fun updateGoogleEvent(
+        gcalDbId: Int, eventId: String, title: String, start: Instant, end: Instant,
+        isAllDay: Boolean, location: String, description: String,
+    ) = guarded {
+        api.updateGoogleEvent(gcalDbId, eventId, simpleEventBody(null, null, title, start, end, isAllDay, location, description))
+            .ensureSuccess()
+    }
+
+    suspend fun deleteGoogleEvent(gcalDbId: Int, eventId: String) =
+        guarded { api.deleteGoogleEvent(gcalDbId, eventId).ensureSuccess() }
+
     suspend fun createHAEvent(
         calendarId: Int, title: String, start: Instant, end: Instant,
         isAllDay: Boolean, location: String, description: String,
     ) = guarded {
-        api.createHAEvent(
-            jsonBody(
-                "calendar_id" to calendarId, "title" to title,
-                "start" to Dates.format(start, isAllDay), "end" to Dates.format(end, isAllDay),
-                "allDay" to isAllDay, "location" to location, "description" to description,
-            )
-        ).ensureSuccess()
+        api.createHAEvent(simpleEventBody("calendar_id", calendarId, title, start, end, isAllDay, location, description))
+            .ensureSuccess()
+    }
+
+    suspend fun updateHAEvent(
+        calendarId: Int, uid: String, title: String, start: Instant, end: Instant,
+        isAllDay: Boolean, location: String, description: String,
+    ) = guarded {
+        api.updateHAEvent(calendarId, uid, simpleEventBody(null, null, title, start, end, isAllDay, location, description))
+            .ensureSuccess()
     }
 
     suspend fun deleteHAEvent(calendarId: Int, uid: String) =
         guarded { api.deleteHAEvent(calendarId, uid).ensureSuccess() }
 
+    /** Body for Google/HA events (no per-event colour). */
+    private fun simpleEventBody(
+        calKey: String?, calId: Int?, title: String, start: Instant, end: Instant,
+        isAllDay: Boolean, location: String, description: String,
+    ) = jsonBody(
+        buildMap {
+            if (calKey != null && calId != null) put(calKey, calId)
+            put("title", title)
+            put("start", Dates.format(start, isAllDay))
+            put("end", Dates.format(end, isAllDay))
+            put("allDay", isAllDay)
+            put("location", location)
+            put("description", description)
+        }
+    )
+
     private fun eventBody(
         calendarId: Int?, title: String, start: Instant, end: Instant,
         isAllDay: Boolean, location: String, description: String, color: String?,

app/src/main/java/com/scarriffle/calendarr/data/remote/CalendarrApi.kt

@@ -170,10 +170,30 @@ interface CalendarrApi {
     @POST("api/google/events")
     suspend fun createGoogleEvent(@Body body: RequestBody): Response<ResponseBody>
 
+    @PUT("api/google/events/{gcalDbId}/{eventId}")
+    suspend fun updateGoogleEvent(
+        @Path("gcalDbId") gcalDbId: Int,
+        @Path("eventId") eventId: String,
+        @Body body: RequestBody,
+    ): Response<ResponseBody>
+
+    @HTTP(method = "DELETE", path = "api/google/events/{gcalDbId}/{eventId}", hasBody = false)
+    suspend fun deleteGoogleEvent(
+        @Path("gcalDbId") gcalDbId: Int,
+        @Path("eventId") eventId: String,
+    ): Response<ResponseBody>
+
     @POST("api/homeassistant/events")
     suspend fun createHAEvent(@Body body: RequestBody): Response<ResponseBody>
 
-    @DELETE("api/homeassistant/events/{calendarId}/{uid}")
+    @PUT("api/homeassistant/events/{calendarId}/{uid}")
+    suspend fun updateHAEvent(
+        @Path("calendarId") calendarId: Int,
+        @Path("uid") uid: String,
+        @Body body: RequestBody,
+    ): Response<ResponseBody>
+
+    @HTTP(method = "DELETE", path = "api/homeassistant/events/{calendarId}/{uid}", hasBody = false)
     suspend fun deleteHAEvent(
         @Path("calendarId") calendarId: Int,
         @Path("uid") uid: String,