refactor(studio): update layout, config, and remove agent activity tracking (#64)

## Summary
- **NLELayout**: Add toolbar slot, composition breadcrumb navigation, improved responsive layout
- **Vite config**: Add full project API (preview, thumbnail, render, file CRUD) for standalone dev mode
- Remove AgentActivityTrack component (replaced by timeline clips)
- Add HTML editor utilities for composition source editing
- Guard setInterval cleanup to dev-only to prevent `vite build` from hanging in CI

🤖 Generated with [Claude Code](https://claude.com/claude-code)

packages/studio/src/hooks/useElementPicker.ts

@@ -156,7 +156,11 @@ export function useElementPicker(
     (
       elementId: string,
       selector: string,
-      op: { type: "inline-style" | "attribute" | "text-content"; property: string; value: string },
+      op: {
+        type: "inline-style" | "attribute" | "text-content";
+        property: string;
+        value: string;
+      },
     ) => {
       const opts = optionsRef.current;
       if (!opts?.workspaceFiles || !opts.onSyncFiles || !elementId) return;