Add authentication system with session-based auth

Implements full auth flows with opaque tokens (not JWT) for easy revocation:
- Login/logout with cookie or bearer token support
- Registration with email verification
- Password reset with one-time tokens
- scrypt password hashing (no external deps)

New files in express/auth/:
- token.ts: 256-bit token generation, SHA-256 hashing
- password.ts: scrypt hashing with timing-safe verification
- types.ts: Session schemas, token types, input validation
- store.ts: AuthStore interface + InMemoryAuthStore
- service.ts: AuthService with all auth operations
- routes.ts: 6 auth endpoints

Modified:
- types.ts: Added user field to Call, requireAuth/requirePermission helpers
- app.ts: JSON body parsing, populates call.user, handles auth errors
- services.ts: Added services.auth
- routes.ts: Includes auth routes

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

express/auth/index.ts

@@ -0,0 +1,10 @@
+// index.ts
+//
+// Barrel export for auth module.
+
+export { hashPassword, verifyPassword } from "./password";
+export { authRoutes } from "./routes";
+export { AuthService } from "./service";
+export { type AuthStore, InMemoryAuthStore } from "./store";
+export { generateToken, hashToken, SESSION_COOKIE_NAME } from "./token";
+export * from "./types";