Wire rate limiter into Frigidaire via requests.Session

[bm1549]

Summary

The autowrap added in #45 silently disabled itself. It patched self._session.request, but Frigidaire never created _session — HTTP went through module-level requests.get/post/put. The AttributeError was swallowed by a bare except, so write spacing, 429/Retry-After handling, and the default timeout have all been no-ops in production. Downstream cas_3403 lockouts that #45 was meant to prevent (bm1549/home-assistant-frigidaire#91) were never actually mitigated by 0.1.3+.

This PR inlines the limiter setup into Frigidaire.__init__: create a requests.Session, wrap request before authenticate() runs (so the auth flow is throttled too — the original incident was an auth storm), and route every HTTP call through self._session. The magic kwargs become explicit, typed, kw-only constructor params. rl_autowrap.py is deleted.

A regression test (test_writes_are_rate_limited_through_session) asserts the wrapper actually fires on a real execute_action call, so this can't silently break again.

Test plan

• pytest — 74 passed in 0.15s
• ruff check . — clean
• mypy frigidaire/ — clean
• Verify with a downstream HA install that scene-driven multi-AC writes no longer trigger cas_3403

🤖 Generated with Claude Code

[bm1549]

@karlg100 heads-up — the autowrap added in #45 has been silently disabled in production since it merged. The enable_autowrap patch targets self._session.request, but Frigidaire never created a _session (HTTP went through module-level requests.get/post/put). The AttributeError got swallowed by a bare except Exception: pass, so write spacing, Retry-After handling, and the default timeout were all no-ops — the cas_3403 lockouts from bm1549/home-assistant-frigidaire#91 were never actually mitigated.

This PR wires the limiter in for real. Tagging you in case you want to verify against your 4-AC scene setup once it lands; that was the canonical reproduction.