Windows startup crash with asyncio NotImplementedError in Playwright

**Describe the bug**
On Windows, running poetry run uvicorn main:app --reload --port 7001 crashes with NotImplementedError during Playwright startup probe. This happens because uvicorn --reload defaults to SelectorEventLoop on Windows, which does not support child process transports needed by Playwrigh

**To Reproduce**
Steps to reproduce the behavior:
1. Run the project on Windows.
2. In backend/, run poetry run uvicorn main:app --reload --port 7001.
3. Watch terminal during startup.
4. See error: Task exception was never retrieved: NotImplementedError.

**Screenshots of backend AND frontend terminal logs**

Backend startup complete. Debug mode is DISABLED.
Task exception was never retrieved
future: exception=NotImplementedError()>
Traceback (most recent call last):
File "...\playwright\_impl\_transport.py", line 120, in connect
self._proc = await asyncio.create_subprocess_exec(...)
File "...\asyncio\base_events.py", line 528, in _make_subprocess_transport
raise NotImplementedError
NotImplementedError
[screenshot_preview] Chromium unavailable — tool disabled.