feat: toast notifications for WorktreeCreate and WorktreeRemove hooks

The backend already parsed and emitted claude:worktree events for these
hooks, and the frontend already updated the store and StatusBar badge.
Add the missing toast notification so the user is informed in real-time
when a worktree is created or removed.

Closes #213

src/lib/tauri.ts

@@ -584,6 +584,12 @@ export async function initializeTauriListeners() {
         event_type === "create" && worktree ? worktree : null
       );
     }
+
+    if (event_type === "create" && worktree) {
+      toastStore.addInfo(`Worktree created: ${worktree.branch}`, "🌿");
+    } else if (event_type === "remove") {
+      toastStore.addInfo("Worktree removed", "🌿");
+    }
   });
   unlisteners.push(worktreeUnlisten);