test: suppress aiohttp BasicAuth deprecation warning

[Divesh-Kshirsagar]

Description

Adds a targeted pytest warning filter for the aiohttp.BasicAuth deprecation warning in pytest.ini.

aiohttp.BasicAuth is intentionally kept because it is still required for proxy authentication, including HTTPS proxy connections. The warning is suppressed only during pytest runs rather than changing the application code.

Type of change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would change existing behavior)
• Documentation update
• Refactor / code cleanup
• Other:

Checklist

• I have tested my changes locally
• If this affects shared logic (extraction, download engine), I also
  applied the equivalent change to moon_cli.py
• I have kept the single-file architecture (no package split)
• I have not added new dependencies without justification in the PR
  description

Screenshots / logs (if applicable)

Tests:

• uv run pytest tests/ — 50 passed
• act -j no-chrome — passed
• act -j ruff — passed

Closes #151