Update project structure and enhance frontend functionality

- Added a new AGENTS.md file to document the project structure and conventions.
- Updated .gitignore to include node_modules and refined cursor rules.
- Introduced new backend and frontend components for improved map interactions, including context menus and controls.
- Enhanced API composables for better admin and authentication functionalities.
- Refactored existing components for cleaner code and improved user experience.
- Updated README.md to clarify production asset serving and user setup instructions.

internal/app/app.go

@@ -20,8 +20,34 @@ type App struct {
 	characters map[string]Character
 	chmu       sync.RWMutex
 
-	gridUpdates  topic
-	mergeUpdates mergeTopic
+	gridUpdates  Topic[TileData]
+	mergeUpdates Topic[Merge]
+}
+
+// GridStorage returns the grid storage path.
+func (a *App) GridStorage() string {
+	return a.gridStorage
+}
+
+// GridUpdates returns the tile updates topic for MapService.
+func (a *App) GridUpdates() *Topic[TileData] {
+	return &a.gridUpdates
+}
+
+// MergeUpdates returns the merge updates topic for MapService.
+func (a *App) MergeUpdates() *Topic[Merge] {
+	return &a.mergeUpdates
+}
+
+// GetCharacters returns a copy of all characters (for MapService).
+func (a *App) GetCharacters() []Character {
+	a.chmu.RLock()
+	defer a.chmu.RUnlock()
+	chars := make([]Character, 0, len(a.characters))
+	for _, v := range a.characters {
+		chars = append(chars, v)
+	}
+	return chars
 }
 
 // NewApp creates an App with the given storage paths and database.