Enhance map functionality and API documentation

- Updated API documentation for the `rebuildZooms` endpoint to clarify its long execution time and response behavior.
- Modified MapView component to manage tile cache invalidation after rebuilding zoom levels, ensuring fresh tile display.
- Introduced a new composable for handling tile cache invalidation state after admin actions.
- Enhanced character icon creation to reflect ownership status with distinct colors.
- Improved loading state handling in various components for better user experience during data fetching.

docs/api.md

@@ -40,7 +40,7 @@ The API is available under the `/map/api/` prefix. Requests requiring authentica
 - **POST /map/api/admin/maps/:id** — update a map (name, hidden, priority).
 - **POST /map/api/admin/maps/:id/toggle-hidden** — toggle map visibility.
 - **POST /map/api/admin/wipe** — wipe grids, markers, tiles, and maps from the database.
-- **POST /map/api/admin/rebuildZooms** — rebuild tile zoom levels.
+- **POST /map/api/admin/rebuildZooms** — rebuild tile zoom levels from base tiles. The operation can take a long time (minutes) when there are many grids; the client should allow for request timeouts or show appropriate loading state. On success returns 200; on failure (e.g. store error) returns 500.
 - **GET /map/api/admin/export** — download data export (ZIP).
 - **POST /map/api/admin/merge** — upload and apply a merge (ZIP with grids and markers).
 - **GET /map/api/admin/wipeTile** — delete a tile. Query: `map`, `x`, `y`.