fix(k1): harden BLE discovery and bridge recovery

tests/test_xgrids_ap_activation.py

@@ -1,3 +1,10 @@
+import asyncio
+
+import pytest
+from bleak.exc import BleakDeviceNotFoundError
+
+import k1link.device_plugins.xgrids_k1.ble.ap_activation as ap_module
+import k1link.device_plugins.xgrids_k1.ble.scanner as scanner_module
 from k1link.device_plugins.xgrids_k1.ble.ap_activation import (
     COMMAND_OFFSET,
     ENABLE_AP_COMMAND,
@@ -33,3 +40,42 @@ def test_ap_control_mode_without_ready_flag_is_not_ready() -> None:
 
 def test_ap_ready_requires_the_reviewed_byte_51_flag() -> None:
     assert is_ap_ready_status(_status(reserved=1))
+
+
+def test_ap_activation_requires_fresh_rediscovery_before_connecting(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    device_id = "synthetic-corebluetooth-uuid"
+    stale_handle = object()
+    rediscovery_calls: list[tuple[str, float]] = []
+    client_calls: list[object] = []
+
+    async def missing_device(address: str, *, timeout: float) -> None:
+        rediscovery_calls.append((address, timeout))
+        return None
+
+    class ForbiddenClient:
+        def __init__(self, device: object, **_kwargs: object) -> None:
+            client_calls.append(device)
+            raise AssertionError("a failed fresh discovery must stop before the BLE write session")
+
+    # Seed the real retained-handle cache so the test fails if the mutating
+    # path ever regresses to discovered_device(...)-first behavior.
+    monkeypatch.setitem(scanner_module._runtime_handles, device_id, stale_handle)  # noqa: SLF001
+    monkeypatch.setattr(
+        ap_module.BleakScanner,
+        "find_device_by_address",
+        missing_device,
+    )
+    monkeypatch.setattr(ap_module, "BleakClient", ForbiddenClient)
+
+    with pytest.raises(BleakDeviceNotFoundError):
+        asyncio.run(
+            ap_module.activate_device_ap_once(
+                device_id,
+                timeout_seconds=1.0,
+            )
+        )
+
+    assert rediscovery_calls == [(device_id, 1.0)]
+    assert client_calls == []