Enhance map updates and component performance

- Updated API documentation to clarify the initial data message structure for real-time tile updates.
- Modified MapView component to load configuration and user data in parallel, improving map loading speed.
- Implemented asynchronous loading for markers after the map is visible, enhancing user experience.
- Introduced batching for tile updates to optimize rendering performance during map updates.
- Refactored character and marker creation functions to utilize dynamic Leaflet imports, improving modularity.

internal/app/handlers/tile.go

@@ -50,13 +50,13 @@ func (h *Handlers) WatchGridUpdates(rw http.ResponseWriter, req *http.Request) {
 	c := h.Map.WatchTiles()
 	mc := h.Map.WatchMerges()
 
-	tileCache := h.Map.GetAllTileCache(ctx)
-
+	// Option 1A: do not send full cache on connect; client requests tiles with cache=0 when missing.
+	// This avoids a huge JSON dump and slow parse on connect when the DB has many tiles.
+	tileCache := []services.TileCache{}
 	raw, _ := json.Marshal(tileCache)
 	fmt.Fprint(rw, "data: ")
 	rw.Write(raw)
 	fmt.Fprint(rw, "\n\n")
-	tileCache = tileCache[:0]
 	flusher.Flush()
 
 	ticker := time.NewTicker(app.SSETickInterval)