fix: refresh tasks snapshot immediately after IPC task mutations

Previously, current_tasks.json was only written at container-start time,
so tasks created (or paused/cancelled/updated) during a session were
invisible to list_tasks until the next invocation.

Add an onTasksChanged callback to IpcDeps, called after every successful
mutation in processTaskIpc (schedule_task, pause_task, resume_task,
cancel_task, update_task). index.ts wires it up to write fresh snapshots
for all registered groups immediately, keeping no new coupling between
ipc.ts and the container layer.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/index.ts

@@ -575,6 +575,21 @@ async function main(): Promise<void> {
     getAvailableGroups,
     writeGroupsSnapshot: (gf, im, ag, rj) =>
       writeGroupsSnapshot(gf, im, ag, rj),
+    onTasksChanged: () => {
+      const tasks = getAllTasks();
+      const taskRows = tasks.map((t) => ({
+        id: t.id,
+        groupFolder: t.group_folder,
+        prompt: t.prompt,
+        schedule_type: t.schedule_type,
+        schedule_value: t.schedule_value,
+        status: t.status,
+        next_run: t.next_run,
+      }));
+      for (const group of Object.values(registeredGroups)) {
+        writeTasksSnapshot(group.folder, group.isMain === true, taskRows);
+      }
+    },
   });
   queue.setProcessMessagesFn(processGroupMessages);
   recoverPendingMessages();