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>

lib/db/schema.ts

@@ -53,12 +53,25 @@ export const sessions = pgTable('sessions', {
   viewerUserId: uuid('viewer_user_id').references(() => users.id, { onDelete: 'set null' }),
   connectionType: text('connection_type'),
   sessionCode: text('session_code'),
+  viewerToken: uuid('viewer_token').default(sql`gen_random_uuid()`),
   startedAt: timestamp('started_at', { withTimezone: true }).defaultNow().notNull(),
   endedAt: timestamp('ended_at', { withTimezone: true }),
   durationSeconds: integer('duration_seconds'),
   notes: text('notes'),
 })
 
+export const enrollmentTokens = pgTable('enrollment_tokens', {
+  id: uuid('id').primaryKey().default(sql`gen_random_uuid()`),
+  token: uuid('token').unique().notNull().default(sql`gen_random_uuid()`),
+  label: text('label'),
+  createdBy: uuid('created_by').references(() => users.id, { onDelete: 'set null' }),
+  createdAt: timestamp('created_at', { withTimezone: true }).defaultNow().notNull(),
+  expiresAt: timestamp('expires_at', { withTimezone: true }),
+  usedCount: integer('used_count').default(0).notNull(),
+  maxUses: integer('max_uses'),
+  revokedAt: timestamp('revoked_at', { withTimezone: true }),
+})
+
 export const invites = pgTable('invites', {
   id: uuid('id').primaryKey().default(sql`gen_random_uuid()`),
   token: uuid('token').unique().notNull().default(sql`gen_random_uuid()`),
@@ -77,3 +90,4 @@ export type Machine = typeof machines.$inferSelect
 export type SessionCode = typeof sessionCodes.$inferSelect
 export type Session = typeof sessions.$inferSelect
 export type Invite = typeof invites.$inferSelect
+export type EnrollmentToken = typeof enrollmentTokens.$inferSelect