perf(wifi): one status fetch per monitor tick instead of three (#411)

* perf(wifi): one status fetch per monitor tick instead of three

The wifi monitor daemon fetched WiFi status + ethernet state before its
AP-mode check, the check internally fetched the same state again (with
retry), and the daemon fetched a third time afterwards — each fetch is
several nmcli subprocess forks, every 30s, forever, even on a perfectly
healthy link.

check_and_manage_ap_mode's decision logic is extracted to
_manage_ap_mode(status, ethernet, ap_active); the new
check_and_manage_ap_mode_with_state() runs the single (retrying) fetch
battery and returns (changed, status, ethernet, ap_active_after) — the
post-state is derivable because state only ever flips via one enable or
one disable. The original bool-returning method delegates, so existing
callers are untouched. The daemon's dead pre-fetch is removed and its
post-check reads use the returned state; the AP-enable retry semantics
(_get_wifi_status_with_retry) are preserved exactly. ~10-15 forks/30s
drops to ~4-6.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FqzC1nzTWL4kaqgMaQZFam

* fix(wifi): add missing type hints on AP-mode state helpers, fix unused-var lint in tests

- check_and_manage_ap_mode_with_state now declares its
  Tuple[bool, WiFiStatus, bool, bool] return type instead of being untyped.
- _manage_ap_mode's status/ethernet_connected/ap_active parameters are now
  typed (WiFiStatus, bool, bool), matching its existing -> bool return hint.
- test_wifi_check_state.py: rename unused unpacked variables (status/
  ethernet/ap_after) to underscore-prefixed names at the three call sites
  that don't use them, leaving the used ones untouched.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01KEZK1P1Q1fu5pcuVrkrCFZ

---------

Co-authored-by: Chuck <chuck@example.com>
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

test/test_wifi_check_state.py

@@ -0,0 +1,92 @@
+"""Tests for check_and_manage_ap_mode_with_state (src/wifi_manager.py).
+
+The wifi monitor daemon used to fetch WiFi status before AND after each
+check on top of the check's own internal fetch — every fetch is several
+nmcli subprocess forks, every 30s, forever. The new API returns the state
+the check observed, so the daemon runs exactly one fetch battery per tick.
+"""
+
+import os
+import sys
+from unittest.mock import MagicMock, patch
+
+import pytest
+
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), ".."))
+
+from src.wifi_manager import WiFiManager, WiFiStatus  # noqa: E402
+
+
+@pytest.fixture
+def wm(tmp_path):
+    with patch.object(WiFiManager, "_load_config", return_value={}, create=True):
+        manager = WiFiManager.__new__(WiFiManager)
+        # minimal attribute setup without running the real __init__
+        manager.config = {"auto_enable_ap_mode": True}
+        manager._disconnected_checks = 0
+        manager._disconnected_checks_required = 3
+        manager._ap_enabled_at = None
+        return manager
+
+
+def _wire(wm, connected, ethernet, ap_active):
+    wm._get_wifi_status_with_retry = MagicMock(
+        return_value=WiFiStatus(connected=connected, ssid="net" if connected else None))
+    wm._is_ethernet_connected = MagicMock(return_value=ethernet)
+    wm._is_ap_mode_active = MagicMock(return_value=ap_active)
+    wm.enable_ap_mode = MagicMock(return_value=(True, "ok"))
+    wm.disable_ap_mode = MagicMock(return_value=(True, "ok"))
+    wm.scan_networks = MagicMock(return_value=([], False))
+    wm._save_cached_scan = MagicMock()
+    wm._FORCE_AP_FLAG_PATH = MagicMock()
+    wm._FORCE_AP_FLAG_PATH.exists.return_value = False
+
+
+class TestWithState:
+    def test_single_fetch_per_call(self, wm):
+        _wire(wm, connected=True, ethernet=False, ap_active=False)
+        wm.check_and_manage_ap_mode_with_state()
+        assert wm._get_wifi_status_with_retry.call_count == 1
+        assert wm._is_ethernet_connected.call_count == 1
+        assert wm._is_ap_mode_active.call_count == 1
+
+    def test_returns_observed_state(self, wm):
+        _wire(wm, connected=True, ethernet=True, ap_active=False)
+        changed, status, ethernet, ap_after = wm.check_and_manage_ap_mode_with_state()
+        assert changed is False
+        assert status.connected is True
+        assert ethernet is True
+        assert ap_after is False
+
+    def test_ap_after_inverts_on_disable(self, wm):
+        """WiFi reconnects while AP is up -> auto-disable -> ap_after False."""
+        _wire(wm, connected=True, ethernet=False, ap_active=True)
+        changed, _status, _ethernet, ap_after = wm.check_and_manage_ap_mode_with_state()
+        assert changed is True
+        assert ap_after is False
+        wm.disable_ap_mode.assert_called_once()
+
+    def test_ap_after_inverts_on_enable(self, wm):
+        """Grace period exhausted with nothing connected -> enable -> True."""
+        _wire(wm, connected=False, ethernet=False, ap_active=False)
+        wm._disconnected_checks = 2  # this call is the 3rd
+        changed, _status, _ethernet, ap_after = wm.check_and_manage_ap_mode_with_state()
+        assert changed is True
+        assert ap_after is True
+        wm.enable_ap_mode.assert_called_once()
+
+    def test_bool_wrapper_is_back_compatible(self, wm):
+        _wire(wm, connected=True, ethernet=False, ap_active=False)
+        assert wm.check_and_manage_ap_mode() is False
+        _wire(wm, connected=True, ethernet=False, ap_active=True)
+        assert wm.check_and_manage_ap_mode() is True
+
+    def test_exception_path_never_raises(self, wm):
+        wm._get_wifi_status_with_retry = MagicMock(side_effect=RuntimeError("nmcli gone"))
+        changed, status, _ethernet, _ap_after = wm.check_and_manage_ap_mode_with_state()
+        assert changed is False
+        assert status.connected is False
+
+
+if __name__ == "__main__":
+    sys.exit(pytest.main([__file__, "-v"]))