debug: watchdog Thread 매 체크마다 로그 기록 (WATCHDOG_CHECK)

watchdog이 실제로 돌고 있는지, 어디서 멈추는지 진단용.
매 5초: WATCHDOG_CHECK silence=Xms connected=true/false
interrupt 시: WATCHDOG_THREAD interrupted
flag 종료 시: WATCHDOG_THREAD stopped

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

app/src/main/java/com/example/medilightv2android/ble/BleManager.kt

@@ -364,12 +364,22 @@ class BleManager private constructor(private val context: Context) {
         debugLogger.info("WATCHDOG_STARTED timeout=${watchdogTimeoutMs}ms")
 
         watchdogJob = Thread({
+            debugLogger.info("WATCHDOG_THREAD running")
             while (watchdogRunning) {
-                try { Thread.sleep(5000) } catch (_: InterruptedException) { break }
-                if (!watchdogRunning) break
-                if (!isConnected.value) continue
+                try { Thread.sleep(5000) } catch (e: InterruptedException) {
+                    debugLogger.warn("WATCHDOG_THREAD interrupted")
+                    break
+                }
+                if (!watchdogRunning) {
+                    debugLogger.info("WATCHDOG_THREAD stopped (flag)")
+                    break
+                }
 
                 val silenceMs = System.currentTimeMillis() - lastRxTimestamp
+                debugLogger.info("WATCHDOG_CHECK silence=${silenceMs}ms connected=${isConnected.value}")
+
+                if (!isConnected.value) continue
+
                 if (silenceMs > watchdogTimeoutMs) {
                     // 직접 로그 기록 (handler 블로킹 무관)
                     debugLogger.error("WATCHDOG_TIMEOUT silence=${silenceMs}ms — forcing reconnect")