Report Jackett setup errors in search results

[q5x-v6e-n7z-6x3]

Summary

Show user-fixable Jackett setup errors in qBittorrent search results and stderr: a missing API key, an unreachable service, or no configured indexers. Check indexers even when thread_count is 1. Raise RuntimeError for malformed XML and Jackett API errors, as requested in review. Update versions.txt to 4.14.

Split from #463 at the maintainer's request. This replaces #464 with the same reviewed commit; the review discussion remains available there.

Review notes

The test file now uses deferred annotations, eliminating the typing import-order conflict with Ruff and Pylint. Small typed response functions remain because strict Pyright rejects untyped inline lambdas passed to monkeypatch.setattr.

Testing

• Jackett tests: 7 passed.
• mypy, pyright, Ruff, pyflakes, Bandit, Pylint, and pycodestyle passed locally on Python 3.14.

[Chocobo1]

Please reopen #464 and push your changes there. I don't want to cross reference when reviewing.