folder migration persister etc

[yujonglee]

Summary

Implements folder organization for sessions with automatic migration of existing sessions to a _default folder structure. Key changes:

• Folder plugin enhancements: Added move_session, create_folder, rename_folder, and delete_folder commands with find_session_dir helper that recursively searches for session directories
• Migration logic: Sessions stored directly under sessions/ (UUID-named folders) are automatically migrated to sessions/_default/ on startup and when detected by the file watcher
• Persister updates: getSessionDir now defaults to _default folder when no folder_id is specified, ensuring consistent path structure
• Folder persister: New persister that scans the directory structure and syncs folder hierarchy to TinyBase store
• Test fixes: Updated path expectations in persister tests to reflect the new _default folder structure

Review & Testing Checklist for Human

• Data safety: Verify the migration logic in migrate_all_uuid_folders and migrate_session_to_default doesn't accidentally delete or corrupt existing session data
• Existing sessions: Test that sessions created before this change are correctly migrated to _default folder and remain accessible
• Folder operations: Test move/create/rename/delete folder operations work correctly and update both filesystem and TinyBase state
• Performance: Check that find_session_dir recursive search doesn't cause noticeable delays with many folders/sessions
• Edge cases: Test behavior when target folder already exists, source doesn't exist, or folder contains nested sessions

Recommended test plan:

1. Create some sessions without folder assignment
2. Restart the app and verify they appear under _default folder
3. Move a session to a new folder and verify filesystem structure matches
4. Check that audio files and other session data are still accessible after migration

Notes

• Link to Devin run: https://app.devin.ai/sessions/074f86c1b26847a8932e55843c8c963d
• Requested by: yujonglee ([email protected]) / @yujonglee

[yujonglee]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• folder migration persister etc #2733 👈 (View in Graphite)
• scaffold folder plugin #2732
• main

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Merge activity

• Jan 2, 10:12 AM UTC: yujonglee added this pull request to the Graphite merge queue.
• Jan 2, 10:13 AM UTC: CI is running for this pull request on a draft pull request (#2736) due to your merge queue CI optimization settings.
• Jan 2, 10:14 AM UTC: Merged by the Graphite merge queue via draft PR: #2736.