incident: SFTPGo outage 2026-09-02 — CT299 tailscaled death + stale lxc-attach recovery

- New incident page documenting CT299 SFTPGo outage (02:18 AWST)
- Root cause: swap exhaustion (43Gi, 100%) killed tailscaled; 5 stale lxc-attach PIDs blocked pct start
- Resolution: killed PIDs 3037951/3334928/3352203/3402511/4004148, pct stop/start 299
- Updated current-state.md with Recent Changes (2026-09-02), bumped updated to 2026-09-04
- Updated log.md with incident entry
- Updated index.md last-updated date

No secrets written. Verified end-to-end: tailscale direct, SFTPGo WebAdmin HTTP 401, SFTP banner SSH-2.0-SFTPGo_2.7.0.

serve.py

@@ -27,6 +27,11 @@ class CleanURLHandler(http.server.SimpleHTTPRequestHandler):
         self.send_header('Access-Control-Allow-Origin', '*')
         super().end_headers()
 
+class CleanURLServer(socketserver.TCPServer):
+    allow_reuse_address = True   # set BEFORE bind: permits instant rebind on restart
+                                 # (TIME-WAIT of prior instance would otherwise
+                                 # cause OSError 98 "Address already in use")
+
 if __name__ == '__main__':
     import argparse
     parser = argparse.ArgumentParser()
@@ -39,6 +44,6 @@ if __name__ == '__main__':
     CleanURLHandler.directory = str(directory)
     os.chdir(directory)
     
-    with socketserver.TCPServer((args.bind, args.port), CleanURLHandler) as httpd:
+    with CleanURLServer((args.bind, args.port), CleanURLHandler) as httpd:
         print(f"Serving {directory} at http://{args.bind}:{args.port}")
         httpd.serve_forever()