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.

internal/app/handlers/admin.go

@@ -334,7 +334,10 @@ func (h *Handlers) APIAdminRebuildZooms(rw http.ResponseWriter, req *http.Reques
 	if h.requireAdmin(rw, req) == nil {
 		return
 	}
-	h.Admin.RebuildZooms(req.Context())
+	if err := h.Admin.RebuildZooms(req.Context()); err != nil {
+		HandleServiceError(rw, err)
+		return
+	}
 	rw.WriteHeader(http.StatusOK)
 }
 

internal/app/services/admin.go

@@ -349,6 +349,6 @@ func (s *AdminService) HideMarker(ctx context.Context, markerID string) error {
 }
 
 // RebuildZooms delegates to MapService.
-func (s *AdminService) RebuildZooms(ctx context.Context) {
-	s.mapSvc.RebuildZooms(ctx)
+func (s *AdminService) RebuildZooms(ctx context.Context) error {
+	return s.mapSvc.RebuildZooms(ctx)
 }

internal/app/services/export.go

@@ -207,8 +207,7 @@ func (s *ExportService) Merge(ctx context.Context, zr *zip.Reader) error {
 	for _, op := range ops {
 		s.mapSvc.SaveTile(ctx, op.MapID, app.Coord{X: op.X, Y: op.Y}, 0, op.File, time.Now().UnixNano())
 	}
-	s.mapSvc.RebuildZooms(ctx)
-	return nil
+	return s.mapSvc.RebuildZooms(ctx)
 }
 
 func (s *ExportService) processMergeJSON(

internal/app/services/map.go

@@ -226,21 +226,33 @@ func (s *MapService) UpdateZoomLevel(ctx context.Context, mapid int, c app.Coord
 		slog.Error("failed to create zoom dir", "error", err)
 		return
 	}
-	f, err := os.Create(fmt.Sprintf("%s/%d/%d/%s.png", s.gridStorage, mapid, z, c.Name()))
-	s.SaveTile(ctx, mapid, c, z, fmt.Sprintf("%d/%d/%s.png", mapid, z, c.Name()), time.Now().UnixNano())
+	path := fmt.Sprintf("%s/%d/%d/%s.png", s.gridStorage, mapid, z, c.Name())
+	relPath := fmt.Sprintf("%d/%d/%s.png", mapid, z, c.Name())
+	f, err := os.Create(path)
 	if err != nil {
+		slog.Error("failed to create tile file", "path", path, "error", err)
 		return
 	}
-	defer f.Close()
-	png.Encode(f, img)
+	if err := png.Encode(f, img); err != nil {
+		f.Close()
+		os.Remove(path)
+		slog.Error("failed to encode tile PNG", "path", path, "error", err)
+		return
+	}
+	if err := f.Close(); err != nil {
+		slog.Error("failed to close tile file", "path", path, "error", err)
+		return
+	}
+	s.SaveTile(ctx, mapid, c, z, relPath, time.Now().UnixNano())
 }
 
 // RebuildZooms rebuilds all zoom levels from base tiles.
-func (s *MapService) RebuildZooms(ctx context.Context) {
+// It can take a long time for many grids; the client should account for request timeouts.
+func (s *MapService) RebuildZooms(ctx context.Context) error {
 	needProcess := map[zoomproc]struct{}{}
 	saveGrid := map[zoomproc]string{}
 
-	s.st.Update(ctx, func(tx *bbolt.Tx) error {
+	if err := s.st.Update(ctx, func(tx *bbolt.Tx) error {
 		b := tx.Bucket(store.BucketGrids)
 		if b == nil {
 			return nil
@@ -254,7 +266,10 @@ func (s *MapService) RebuildZooms(ctx context.Context) {
 		})
 		tx.DeleteBucket(store.BucketTiles)
 		return nil
-	})
+	}); err != nil {
+		slog.Error("RebuildZooms: failed to update store", "error", err)
+		return err
+	}
 
 	for g, id := range saveGrid {
 		f := fmt.Sprintf("%s/grids/%s.png", s.gridStorage, id)
@@ -271,6 +286,7 @@ func (s *MapService) RebuildZooms(ctx context.Context) {
 			needProcess[zoomproc{p.c.Parent(), p.m}] = struct{}{}
 		}
 	}
+	return nil
 }
 
 // ReportMerge sends a merge event.