feat: add cross-component playhead scroll synchronization

src/stores/projectStore.ts

@@ -109,6 +109,12 @@ interface ProjectState {
   canRedo: boolean;
   undoDescription: string | null;
   redoDescription: string | null;
+
+  // Cross-component scroll request state
+  requestMainContentScroll: (beatPosition: number) => void;
+  requestPianoRollScroll: (beatPosition: number) => void;
+  mainContentScrollRequest: number | null;
+  pianoRollScrollRequest: number | null;
   
   // Actions
   setProjectName: (name: string) => void;
@@ -340,6 +346,10 @@ export const useProjectStore = create<ProjectState>((set, get) => {
     recordingNotes: [],
     recordingOriginalPlayhead: 0,
 
+    // Initial cross-component scroll request state
+    mainContentScrollRequest: null,
+    pianoRollScrollRequest: null,
+
     // Actions
     setProjectName: (name: string) => {
       try {
@@ -793,6 +803,14 @@ export const useProjectStore = create<ProjectState>((set, get) => {
       set({ autoScrollEnabled: enabled });
     },
 
+    requestMainContentScroll: (beatPosition: number) => {
+      set({ mainContentScrollRequest: beatPosition });
+    },
+
+    requestPianoRollScroll: (beatPosition: number) => {
+      set({ pianoRollScrollRequest: beatPosition });
+    },
+
     startPlaying: async () => {
       await KGCore.instance().startPlaying();
       set({ isPlaying: true, autoScrollEnabled: true });