feat: implement CommandPalette for quick filter and search

- Add text search across all focus items
- Support filter commands: type: and stale:
- Keyboard navigation with arrow keys + Enter
- Click to select items
- Escape or backdrop click to close
- 17 tests covering search, filters, keyboard nav, and empty state

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src-tauri/src/lib.rs

@@ -109,6 +109,9 @@ pub fn run() {
     tracing::info!("Starting Mission Control");
 
     // Build tauri-specta builder for type-safe IPC
+    // Note: read_state/write_state/clear_state use serde_json::Value which doesn't
+    // implement specta::Type, so they're excluded from the builder but kept in
+    // the invoke_handler via generate_handler!
     let builder = Builder::<tauri::Wry>::new().commands(collect_commands![
         commands::greet,
         commands::get_lore_status,
@@ -116,9 +119,6 @@ pub fn run() {
         commands::sync_now,
         commands::reconcile,
         commands::quick_capture,
-        commands::read_state,
-        commands::write_state,
-        commands::clear_state,
     ]);
 
     // Export TypeScript bindings in debug builds