1. Folder selection now recursively includes notes from subfolders
2. + button creates a new folder with inline rename (Tauri command + UI)
3. Note list items show full path when note is in a subdirectory
4. Remove flat vault migration banner and all related code (Rust commands,
hook, component, smoke test) — subfolders are now first-class
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Build FolderTree component that renders the vault's directory
structure below the TYPES sections. Integrates with SidebarSelection
to filter the note list by folder path. Styled to match the
ui-design.pen "Folder Tree Sidebar" frame with Phosphor folder
icons, blue highlight for selected folder, and indented children
with guide lines. Wire folder data from useVaultLoader → App → Sidebar.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
