fix(client): Improve resilience on transient network and auth failures

[dansrogers]

Summary & Overview

This pull request hardens OverkizClient against transient network drops, socket timeouts, and session expirations. It adds automatic exponential backoff retry decorators to register_event_listener(), introduces defensive error trapping in relogin() and refresh_listener() backoff callbacks, and ensures _event_listener_id is consistently invalidated and reset upon re-authentication.

Motivation & Problem Statement

During periods of network instability or Overkiz/Somfy cloud maintenance:

1. Unhandled Network Drops during Event Registration: register_event_listener() was only decorated with @retry_on_concurrent_requests. A socket timeout, DNS failure, or transient 401 NotAuthenticatedError during listener registration raised an immediate exception instead of triggering retry backoff and automated session recovery.
2. Backoff Callback Crashes: In relogin() and refresh_listener() backoff callbacks, if a network outage was ongoing when the backoff handler fired, unhandled ClientError, TimeoutError, or OSError exceptions crashed the backoff lifecycle prematurely.
3. Stale Listener ID Retention: When re-authenticating after session eviction, a stale _event_listener_id could be retained, preventing clean event listener re-registration.

Changes Made

• Backoff Retries on register_event_listener():
  Decorated register_event_listener() with @retry_on_connection_failure and @retry_on_auth_error alongside @retry_on_concurrent_requests in pyoverkiz/client.py.
• Defensive Callback Handlers:
  Wrapped client.login() in relogin() and client.register_event_listener() in refresh_listener() with try/except (TimeoutError, ClientError, OSError) blocks to log warnings without terminating backoff sequences.
• Listener ID Invalidation:
  • Added public helper reset_event_listener_id(self) -> None on OverkizClient.
  • Added explicit listener ID reset inside login() and within relogin() / refresh_listener() handlers.
• Test Suite Expansion:
  • Added unit test coverage in tests/test_client.py for retry policies on register_event_listener and error handling during backoff callbacks.
  • Added comprehensive adversarial test suite in tests/test_adversarial_transport_auth.py covering cascading faults, prolonged outages, 502/503 server maintenance, and fast-failure on non-retryable bad credentials (BadCredentialsError).

Test Coverage & Verification

• Full Test Suite: 570+ tests passed.
• Static Analysis & Pre-commit: All 11 prek / ruff / mypy / ty checks passed cleanly.

============================= test session starts ==============================
collected 570 items
570 passed

Pre-commit & Static Analysis Verification Log

ruff check...............................................................Passed
ruff format..............................................................Passed
trim trailing whitespace.................................................Passed
fix end of files.........................................................Passed
check json...............................................................Passed
check yaml...............................................................Passed
check for added large files..............................................Passed
don't commit to branch...................................................Passed
Lint GitHub Actions workflow files.......................................Passed
mypy.....................................................................Passed
ty check.................................................................Passed

Cross-Repository Context & Companion PR

• Home Assistant Core Companion PR: fix(overkiz): Improve coordinator resilience against transient connectivity and auth errors home-assistant/core#180222
• Defense-in-Depth Architecture:
  • Layer 1 (This PR - python-overkiz-api): Hardens low-level HTTP transport retries, session backoff, and event listener lifecycle management.
  • Layer 2 (Downstream - home-assistant/core): Implements coordinator state self-healing, execution TTL cleanup (EXECUTION_TTL = 60s), and full device state resynchronization (_need_full_resync).
• Decoupled Deployment: This PR does not alter public API signatures and maintains 100% backward compatibility with existing downstream consumers. Downstream integrations can take advantage of these resilience enhancements immediately upon package update.