android: fix key regeneration, Clear DB, uasync eventfd, udp log from config

- jni_on_event: fix JNI_EDETACHED — AttachCurrentThread/DetachCurrentThread
- u_async.c: pipe→eventfd for reliable cross-thread wakeup
  add process_posted_tasks in poll() path, fix EINTR (saved_errno)
- bridge_debug_hook: keep udp_log_write, remove mutex from udp_log
- memory_pool.c: alloc/free logs INFO→DEBUG (reduce spam)
- instance_lite.c: chat_event_set_handler before ensure_keys,
  KEYS_GENERATED events, fchmod 0600 on keys.conf,
  UDP log from config [log_udp] section, regenerate_trampoline
- config_parser: parse [log_udp] ip/port
- NativeLib.kt: remove callbacksSet, simplify init/stop/destroy
- ChatViewModel.kt: unified event callback in init, pubKey StateFlow,
  requestRegenerateKeys, clearState fix
- SettingsScreen.kt: pubKey.collectAsState(), Clear DB via restart()
- HeadlessService.kt: remove setUdpLogTarget (now from config)
- android_udp_log.c: simplified — no mutex, buffer+send+timer in one thread
- utun_instance.c: NULL-check tcp_connections before destroy
- chat_event.h: +CHAT_EVT_KEYS_GENERATED 11, -NODE_CHANGED
- logreceiver: UDP log receiver tool

lib/debug_config.c

@@ -409,7 +409,9 @@ void debug_output(debug_level_t level, debug_category_t category_idx,
     
     /* Add file:line if enabled */
     if (g_debug_config.file_line_enabled && file) {
-        offset += snprintf(buffer + offset, remaining, "(%s:%d) ", file, line);
+        const char* bn = strrchr(file, '/');
+        bn = bn ? bn + 1 : file;
+        offset += snprintf(buffer + offset, remaining, "(%s:%d) ", bn, line);
         remaining = BUFFER_SIZE - offset;
     }