feat(timer): wire VisualTimer to tasks with notifications and persistence

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src-tauri/src/commands/mod.rs

@@ -4,5 +4,6 @@ pub mod hardware;
 pub mod history;
 pub mod models;
 pub mod tasks;
+pub mod timer;
 pub mod transcription;
 pub mod windows;