feat(middleware): add JWT auth module with bcryptjs login and protected routes

- src/api/middleware/auth.ts: signToken, verifyToken, authMiddleware (Bearer JWT, 24h expiry)
- src/api/routes/auth.ts: POST /api/auth/login (bcryptjs verify) and GET /api/auth/me (protected)
- src/index.ts: mount auth router at /api/auth
- tests/api/auth.test.ts: 7 tests covering login success, wrong password, no token, invalid token, valid access
- Using bcryptjs (pure JS) instead of bcrypt (requires Visual Studio on Windows)

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

display/middleware/src/index.ts

@@ -1,5 +1,6 @@
 import express from 'express';
 import cors from 'cors';
+import authRouter from './api/routes/auth';
 
 const app = express();
 const PORT = process.env.PORT ? parseInt(process.env.PORT) : 4000;
@@ -11,6 +12,8 @@ app.get('/health', (_req, res) => {
   res.json({ status: 'ok', timestamp: new Date().toISOString() });
 });
 
+app.use('/api/auth', authRouter);
+
 if (require.main === module) {
   app.listen(PORT, () => {
     console.log(`Middleware server running on port ${PORT}`);