CLI version check timeout can hang indefinitely while waiting for termination

### Summary

`SubprocessCLITransport._check_claude_version()` has a two-second timeout, but its cleanup performs an unbounded process wait outside that timeout.

### Affected code

`src/claude_agent_sdk/_internal/transport/subprocess_cli.py:1024-1065`

### Current behavior

The `anyio.fail_after(2)` scope covers process creation and reading the version output. In `finally`, the code calls:

```python
version_process.terminate()
await version_process.wait()
```

The wait is outside the timeout and there is no kill fallback. If the executable ignores or fails to respond to SIGTERM, `wait()` never returns.

Exceptions are also suppressed, so this path does not expose useful diagnostic information.

### Why this matters

The version check runs during transport connection. A stale, wrapped, broken, or malicious executable at the configured CLI path can therefore hang every SDK connection indefinitely despite the documented two-second timeout.

### Expected behavior

The entire probe, including process cleanup and reaping, should have a finite upper bound.

### Possible fix

Use bounded subprocess shutdown:

1. Terminate the process.
2. Wait for a short bounded interval.
3. Kill it if still running.
4. Await/reap it under another bounded interval.
5. Preserve cancellation semantics while suppressing only expected cleanup errors.

A regression test can use a mocked process whose first `wait()` does not complete and assert that `kill()` is called and connection continues within the deadline.

This follow-up was mentioned as out of scope in PR #1082, but I found no dedicated issue or active implementation.

### Environment

- Repository revision: current `main` audit at SDK version 0.2.128
- Bundled CLI version: 2.1.220
- Python test suite: 1,291 passed, 5 skipped
- Ruff and mypy: clean

I searched the existing issues and pull requests using the affected symbols and behavior before filing this.