Add Python agent, WebSocket relay, real viewer, enrollment tokens

- WebSocket relay service (FastAPI) bridges agents and viewers
- Python agent with screen capture (mss), input control (pynput),
  script execution, and auto-reconnect
- Windows service wrapper, PyInstaller spec, NSIS installer for
  silent mass deployment (RemoteLink-Setup.exe /S /SERVER= /ENROLL=)
- Enrollment token system: admin generates tokens, agents self-register
- Real WebSocket viewer replaces simulated canvas
- Linux agent binary served from /downloads/remotelink-agent-linux
- DB migration 0002: viewer_token on sessions, enrollment_tokens table
- Sign-up pages cleaned up (invite-only redirect)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

agent/service_win.py

@@ -0,0 +1,98 @@
+"""
+Windows Service wrapper for the RemoteLink Agent.
+Installs/uninstalls/runs as a Windows Service via pywin32.
+
+Usage:
+  remotelink-agent-service.exe install
+  remotelink-agent-service.exe start
+  remotelink-agent-service.exe stop
+  remotelink-agent-service.exe remove
+"""
+
+import sys
+import os
+import asyncio
+import logging
+
+# Only import win32 on Windows
+if sys.platform == "win32":
+    import win32serviceutil
+    import win32service
+    import win32event
+    import servicemanager
+
+    class RemoteLinkService(win32serviceutil.ServiceFramework):
+        _svc_name_ = "RemoteLinkAgent"
+        _svc_display_name_ = "RemoteLink Agent"
+        _svc_description_ = "RemoteLink remote support agent service"
+
+        def __init__(self, args):
+            win32serviceutil.ServiceFramework.__init__(self, args)
+            self.stop_event = win32event.CreateEvent(None, 0, 0, None)
+            self._loop = None
+            self._agent = None
+
+        def SvcStop(self):
+            self.ReportServiceStatus(win32service.SERVICE_STOP_PENDING)
+            if self._agent:
+                self._agent.stop()
+            win32event.SetEvent(self.stop_event)
+
+        def SvcDoRun(self):
+            servicemanager.LogMsg(
+                servicemanager.EVENTLOG_INFORMATION_TYPE,
+                servicemanager.PYS_SERVICE_STARTED,
+                (self._svc_name_, ""),
+            )
+            self._run()
+
+        def _run(self):
+            # Set up logging to Windows Event Log + file
+            log_path = os.path.join(
+                os.environ.get("PROGRAMDATA", "C:\\ProgramData"),
+                "RemoteLink", "agent.log"
+            )
+            os.makedirs(os.path.dirname(log_path), exist_ok=True)
+            logging.basicConfig(
+                level=logging.INFO,
+                format="%(asctime)s [%(levelname)s] %(message)s",
+                handlers=[logging.FileHandler(log_path)],
+            )
+
+            # Import here to avoid circular issues when this module is imported
+            from agent import Agent, load_config, heartbeat
+            import json
+
+            config = load_config()
+            if not config:
+                logging.error("No agent config found. Run enrollment first.")
+                return
+
+            self._loop = asyncio.new_event_loop()
+            asyncio.set_event_loop(self._loop)
+
+            agent = Agent(
+                config["server_url"],
+                config["machine_id"],
+                config["access_key"],
+                config.get("relay_url", ""),
+            )
+            self._agent = agent
+
+            try:
+                self._loop.run_until_complete(agent.run())
+            finally:
+                self._loop.close()
+
+
+    if __name__ == "__main__":
+        if len(sys.argv) == 1:
+            servicemanager.Initialize()
+            servicemanager.PrepareToHostSingle(RemoteLinkService)
+            servicemanager.StartServiceCtrlDispatcher()
+        else:
+            win32serviceutil.HandleCommandLine(RemoteLinkService)
+
+else:
+    print("Windows service wrapper — only runs on Windows.")
+    sys.exit(1)