fix(test): pin aiohttp<3.14 to work around aioresponses incompatibility

[shbatm]

Summary

• CI has been red on both the 3.11 and 3.14 test jobs since the runner started picking up aiohttp 3.14, which added a required stream_writer kwarg to ClientResponse.__init__. aioresponses 0.7.9 (latest release) doesn't pass it when building mock responses, so every test that exercises Connection.request() through aioresponses fails with TypeError: ClientResponse.__init__() missing 1 required keyword-only argument: 'stream_writer' (11 failures).
• Upstream fix is open but unreleased: fix: support aiohttp 3.14 required stream_writer argument pnuckowski/aioresponses#288.
• Pinned aiohttp<3.14 in requirements-test.txt only — this doesn't touch the library's own aiohttp>=3.8.1 floor in pyproject.toml/requirements.txt, so it has no effect on downstream consumers (e.g. Home Assistant Core, which currently pins aiohttp==3.13.5 anyway).
• Left the aiohttp.BasicAuth deprecation warning (also present in the logs) as-is for now — fixing it properly means switching to aiohttp.encode_basic_auth(), which requires bumping the floor to aiohttp>=3.14.0. That would make PyISY's requirements incompatible with HA Core's current aiohttp==3.13.5 pin, so it's out of scope here.

Test plan

• pytest — 448 passed locally with aiohttp==3.13.5 installed
• pre-commit run --all-files — clean
• CI green on both Python 3.11 and 3.14 jobs

🤖 Generated with Claude Code

https://claude.ai/code/session_01PPpQYEKnQFCiy3GS3D2fKs