Retry httpcore RemoteProtocolError in SpanPanelApi

[NickBorgersOnLowSecurityNode]

This seeks to close SpanPanel#156

Motivation

• The integration experienced intermittent RemoteProtocolError: Server disconnected without sending a response caused by httpx/httpcore connection-pool reuse of server-closed keep-alive connections.
• These transient protocol disconnects caused panels to be marked offline and generated aggressive retry traffic and HA event-loop pressure.
• The intent is to recover transparently from this client-side race by recreating the client and retrying the operation once on protocol disconnects.
• This mirrors fixes applied in other Home Assistant integrations and avoids disabling keep-alive globally.

Description

• Add handling for httpcore.RemoteProtocolError by importing RemoteProtocolError and adding helper methods async def _recreate_client and async def _call_with_protocol_retry to recreate the SpanPanelClient and retry once.
• Wrap critical client operations (authenticate, get_status, get_panel_state, get_circuits, get_storage_soe, set_circuit_relay, set_circuit_priority, and get_all_data) with _call_with_protocol_retry to perform a single recreate-and-retry on protocol disconnects.
• Convert the low-level protocol retry into a SpanPanelConnectionError if the retry also fails to provide a consistent error surface.
• Add unit tests test_get_all_data_retries_on_remote_protocol_error and test_get_all_data_remote_protocol_error_after_retry to tests/test_span_panel_api.py to validate retry and failure-after-retry behavior.

Testing

• Added unit tests in tests/test_span_panel_api.py covering successful retry and failure-after-retry of get_all_data when httpcore.RemoteProtocolError is raised.
• Attempted to run PYENV_VERSION=3.11.12 pyenv exec python -m pytest tests/test_span_panel_api.py in the local environment which failed with ModuleNotFoundError: No module named 'span_panel_api' due to the external span-panel-api dependency not being available here.
• No additional automated test suites were executed in this environment because the test dependency prevented running the new tests.

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Codex Task

[NickBorgers]

Testing Performed

I tested the changes on this branch and verified the implementation works correctly.

Test Results

API Tests (54 passed)

tests/test_span_panel_api.py - 54 passed in 0.36s

The two new tests added by this PR both pass:

• ✅ test_get_all_data_retries_on_remote_protocol_error - Verifies that a single RemoteProtocolError is recovered by recreating the client and retrying
• ✅ test_get_all_data_remote_protocol_error_after_retry - Verifies that persistent errors after retry are converted to SpanPanelConnectionError

Full Test Suite (221 passed, 1 skipped)
All other tests in the repository pass without regression.

Linting

ruff check - All checks passed!

Implementation Verification

The retry logic is correctly implemented:

1. Import: RemoteProtocolError is properly imported from httpcore
2. _recreate_client method: Safely closes existing client and creates a new one with stored parameters
3. _call_with_protocol_retry method: Wraps operations with a single retry on protocol disconnect, converting to SpanPanelConnectionError if the retry also fails
4. Coverage: The retry logic is applied to all critical client operations:
   • authenticate
   • get_status
   • get_panel_state
   • get_circuits
   • get_storage_soe
   • set_circuit_relay
   • set_circuit_priority
   • get_all_data

The implementation aligns with the goal of transparently recovering from transient RemoteProtocolError: Server disconnected without sending a response errors caused by httpx/httpcore connection-pool reuse of server-closed keep-alive connections.