/loop slash command cron task lost after session resume

## Summary
When a user creates a cron task using the `/loop` slash command via `query()`, the task works as expected during the live session. However, after the session is closed and subsequently resumed — either via `query({ resume: sessionId })`, the background cron task is completely lost and fails to persist. SDK consumers have no way to recover or re-register the active loop from the resumed session history.

## Environment
- `@anthropic-ai/claude-agent-sdk` : 0.3.168

- Node.js: 22.x

- Consumer: TypeScript backend utilizing session resume capabilities

## Reproduction
1. Start a session with `query({ prompt, options: { ... } })`.

2. Send `/loop ` (or any cron-based slash command) to successfully register a background task.

3. Verify that the task triggers successfully at least once during the active stream.

4. End the current process / close the connection to terminate the live session.

5. In a fresh process, resume the session using `query({ resume: sessionId })`.

6. Query the AI or SDK state to check active background tasks (e.g., inspecting the active cron list).

## Actual behaviour
The session history resumes successfully, but the background cron task created by `/loop` disappears completely.

- No background triggers occur after the resume.

- The SDK does not automatically re-register or re-schedule the cron tasks found in the persisted transcript.

- When querying the AI or SDK for active loops after resumption, the returned `CronList` result is completely empty, leaving consumers with no way to manually inspect or revive the tasks.

## Expected behaviour
The SDK should natively parse the persisted session history upon `resume` and automatically re-register any active background cron tasks (`/loop`) associated with that session.