fix(ble): never give up while user has device selected

The reconnect policy previously capped at 10 consecutive failures and
emitted a permanent disconnect, which terminated the reconnect loop and
required the user to manually re-select the device. BleRadioTransport is
only ever instantiated for the user-selected address (verified via
SharedRadioInterfaceService.startTransportLocked), so the only legitimate
permanent-disconnect path is explicit close() owned by the service layer.

- BleRadioTransport: pass maxFailures = Int.MAX_VALUE; backoff still
  caps at 60 s so battery impact remains bounded.
- BleExceptionClassifier: flip UnmetRequirementException (BT off /
  permission missing) to non-permanent — both can resolve without the
  user re-selecting the device.
- Test: replace the old 'gives up after DEFAULT_MAX_FAILURES' test with
  an inverted contract test that runs past the legacy threshold and
  asserts the policy never emits isPermanent=true on its own.

core/ble/src/commonMain/kotlin/org/meshtastic/core/ble/BleExceptionClassifier.kt

@@ -26,7 +26,9 @@ import com.juul.kable.UnmetRequirementException
 /**
  * Classification of a BLE-layer exception for the transport layer to act on.
  *
- * @property isPermanent `true` if the condition won't resolve without user intervention (e.g. Bluetooth disabled).
+ * @property isPermanent `true` if the condition cannot resolve without explicit user re-selection of the device.
+ *   Currently always `false` — all known BLE exceptions can resolve without user intervention (BT toggling, permission
+ *   grants, transient GATT errors). Reserved for future use.
  * @property gattStatus the platform GATT status code when available (Android-specific).
  * @property message a human-readable description of the failure.
  */
@@ -50,6 +52,9 @@ fun Throwable.classifyBleException(): BleExceptionInfo? = when (this) {
     is GattRequestRejectedException ->
         BleExceptionInfo(isPermanent = false, message = "GATT request rejected (busy)")
     is UnmetRequirementException ->
-        BleExceptionInfo(isPermanent = true, message = message ?: "Bluetooth LE unavailable")
+        // Bluetooth disabled or runtime permission missing. Both can resolve without re-selecting the
+        // device (user re-enables BT, or grants permission). Surface as transient so the transport keeps
+        // retrying; UI can show a hint based on the message.
+        BleExceptionInfo(isPermanent = false, message = message ?: "Bluetooth LE unavailable")
     else -> null
 }