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/installer.nsi

@@ -0,0 +1,116 @@
+; RemoteLink Agent NSIS Installer
+; Requires: NSIS 3.x, the dist/ folder from PyInstaller build
+;
+; Build: makensis installer.nsi
+; Silent install: RemoteLink-Setup.exe /S
+; Silent install + enroll: RemoteLink-Setup.exe /S /SERVER=https://myserver.com /ENROLL=mytoken
+
+!define APP_NAME "RemoteLink Agent"
+!define APP_VERSION "1.0.0"
+!define APP_PUBLISHER "RemoteLink"
+!define APP_URL "https://remotelink.example.com"
+!define INSTALL_DIR "$PROGRAMFILES64\RemoteLink"
+!define SERVICE_EXE "remotelink-agent-service.exe"
+!define AGENT_EXE "remotelink-agent.exe"
+!define REG_KEY "Software\RemoteLink\Agent"
+!define UNINSTALL_KEY "Software\Microsoft\Windows\CurrentVersion\Uninstall\RemoteLinkAgent"
+
+; Installer settings
+Name "${APP_NAME} ${APP_VERSION}"
+OutFile "RemoteLink-Setup.exe"
+InstallDir "${INSTALL_DIR}"
+InstallDirRegKey HKLM "${REG_KEY}" "InstallDir"
+RequestExecutionLevel admin
+SetCompressor /SOLID lzma
+
+; Command-line parameters
+Var ServerURL
+Var EnrollToken
+
+; Modern UI
+!include "MUI2.nsh"
+!include "LogicLib.nsh"
+!include "nsProcess.nsh"
+
+!define MUI_ABORTWARNING
+!define MUI_ICON "assets\icon.ico"
+!define MUI_UNICON "assets\icon.ico"
+
+!insertmacro MUI_PAGE_WELCOME
+!insertmacro MUI_PAGE_DIRECTORY
+!insertmacro MUI_PAGE_INSTFILES
+!insertmacro MUI_PAGE_FINISH
+
+!insertmacro MUI_UNPAGE_CONFIRM
+!insertmacro MUI_UNPAGE_INSTFILES
+
+!insertmacro MUI_LANGUAGE "English"
+
+; ── Functions ─────────────────────────────────────────────────────────────────
+
+Function .onInit
+    ; Parse command-line switches /SERVER= and /ENROLL=
+    ${GetParameters} $R0
+    ${GetOptions} $R0 "/SERVER=" $ServerURL
+    ${GetOptions} $R0 "/ENROLL=" $EnrollToken
+
+    ; Silent mode: skip UI if /S passed
+    IfSilent 0 +2
+    SetSilent silent
+FunctionEnd
+
+; ── Main install section ──────────────────────────────────────────────────────
+
+Section "Install" SEC_MAIN
+    SetOutPath "${INSTALL_DIR}"
+
+    ; Stop existing service if running
+    nsExec::ExecToLog '"${INSTALL_DIR}\${SERVICE_EXE}" stop'
+    nsExec::ExecToLog '"${INSTALL_DIR}\${SERVICE_EXE}" remove'
+    Sleep 1000
+
+    ; Copy files from PyInstaller dist/
+    File "dist\remotelink-agent.exe"
+    File "dist\remotelink-agent-service.exe"
+
+    ; Write registry
+    WriteRegStr HKLM "${REG_KEY}" "InstallDir" "${INSTALL_DIR}"
+    WriteRegStr HKLM "${REG_KEY}" "Version" "${APP_VERSION}"
+
+    ; Run enrollment if tokens were provided (silent mass-deploy)
+    ${If} $ServerURL != ""
+    ${AndIf} $EnrollToken != ""
+        DetailPrint "Enrolling with server $ServerURL…"
+        nsExec::ExecToLog '"${INSTALL_DIR}\${AGENT_EXE}" --server "$ServerURL" --enroll "$EnrollToken"'
+    ${EndIf}
+
+    ; Install + start Windows service
+    DetailPrint "Installing Windows service…"
+    nsExec::ExecToLog '"${INSTALL_DIR}\${SERVICE_EXE}" install'
+    nsExec::ExecToLog '"${INSTALL_DIR}\${SERVICE_EXE}" start'
+
+    ; Create uninstaller
+    WriteUninstaller "${INSTALL_DIR}\Uninstall.exe"
+    WriteRegStr HKLM "${UNINSTALL_KEY}" "DisplayName" "${APP_NAME}"
+    WriteRegStr HKLM "${UNINSTALL_KEY}" "UninstallString" "${INSTALL_DIR}\Uninstall.exe"
+    WriteRegStr HKLM "${UNINSTALL_KEY}" "DisplayVersion" "${APP_VERSION}"
+    WriteRegStr HKLM "${UNINSTALL_KEY}" "Publisher" "${APP_PUBLISHER}"
+    WriteRegDWORD HKLM "${UNINSTALL_KEY}" "NoModify" 1
+    WriteRegDWORD HKLM "${UNINSTALL_KEY}" "NoRepair" 1
+SectionEnd
+
+; ── Uninstall section ─────────────────────────────────────────────────────────
+
+Section "Uninstall"
+    nsExec::ExecToLog '"${INSTALL_DIR}\${SERVICE_EXE}" stop'
+    nsExec::ExecToLog '"${INSTALL_DIR}\${SERVICE_EXE}" remove'
+    Sleep 1000
+
+    Delete "${INSTALL_DIR}\remotelink-agent.exe"
+    Delete "${INSTALL_DIR}\remotelink-agent-service.exe"
+    Delete "${INSTALL_DIR}\Uninstall.exe"
+    RMDir "${INSTALL_DIR}"
+
+    DeleteRegKey HKLM "${REG_KEY}"
+    DeleteRegKey HKLM "${UNINSTALL_KEY}"
+SectionEnd