fix: RDP tunnel status adopts detached/wild tunnels instead of false-disabled

- _rdp_find_tunnel_process(): find ssh.exe hosting -R 8080 forwarding via CIM
- _rdp_status(): adopt actual tunnel process when pid file stale/missing
- _rdp_enable(): adopt existing tunnel instead of spawning duplicate that
  fails on 'remote port forwarding failed' (8080 occupied)
- Fixes 2026-07-23 incident: tunnel alive but dashboard showed disabled,
  repeated enable attempts failed because port was occupied by working tunnel

xmpp_agent_core.py

@@ -317,6 +317,15 @@ def _rdp_enable():
     except Exception:
         pass
     _rdp_kill_tunnel()
+    # 收养现存隧道：如果有 ssh 进程已在跑 -R 8080 转发（比如 bot 崩溃后留下的
+    # detached ssh、或状态文件丢失后的野生隧道），直接写入 pid 文件收养，
+    # 不再起新进程——否则新 ssh 会因 8080 被占报 "remote port forwarding failed"，
+    # 导致 dashboard 永远显示 disabled（2026-07-23 事故）。
+    _existing = _rdp_find_tunnel_process()
+    if _existing:
+        _rdp_adopt_tunnel(_existing)
+        log(f'RDP: tunnel already running (PID {_existing}), adopted — no new ssh needed')
+        return True, f'RDP access enabled (adopted existing tunnel, PID {_existing})'
     # Health check: if RDP not responding, auto-restore
     _t.sleep(2)
     if not _rdp_health_check():
@@ -403,6 +412,36 @@ def _rdp_kill_tunnel():
         except Exception:
             pass
 
+def _rdp_find_tunnel_process():
+    """Find a running ssh.exe hosting the -R 8080:localhost:3389 reverse tunnel.
+    Returns PID or None. Used to adopt tunnels started outside _rdp_enable
+    (e.g. by a crashed/restarted bot that left a detached ssh behind)."""
+    import subprocess as _sp
+    try:
+        # 纯单引号写法：避免 powershell -Command 下双引号转义失效
+        ps_cmd = ("Get-CimInstance Win32_Process | "
+                  "Where-Object { $_.Name -eq 'ssh.exe' -and $_.CommandLine -like '*8080:localhost:3389*' } | "
+                  "Select-Object -ExpandProperty ProcessId")
+        r = _sp.run(['powershell', '-NoProfile', '-Command', ps_cmd],
+                    capture_output=True, text=True, timeout=15)
+        for line in r.stdout.splitlines():
+            line = line.strip()
+            if line.isdigit():
+                return int(line)
+    except Exception:
+        pass
+    return None
+
+def _rdp_adopt_tunnel(pid):
+    """Write pid file for an externally-started tunnel so status tracking works."""
+    try:
+        with open(_RDP_PID_FILE, 'w') as f:
+            f.write(str(pid))
+        log(f'RDP: adopted existing tunnel (PID {pid})')
+        return True
+    except Exception:
+        return False
+
 def _rdp_status():
     import subprocess as _sp, winreg as _wr
     tunnel_on = False
@@ -413,6 +452,12 @@ def _rdp_status():
             tunnel_on = 'ssh.exe' in r.stdout
         except Exception:
             pass
+    # pid file missing or process dead → look for an actual tunnel process and adopt it
+    if not tunnel_on:
+        found = _rdp_find_tunnel_process()
+        if found:
+            _rdp_adopt_tunnel(found)
+            tunnel_on = True
     rdp_on = False
     try:
         k = _wr.OpenKey(_wr.HKEY_LOCAL_MACHINE, r'SYSTEM\CurrentControlSet\Control\Terminal Server', 0, _wr.KEY_READ)