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/routes.ts

@@ -2,6 +2,7 @@
 
 import nunjucks from "nunjucks";
 import { DateTime } from "ts-luxon";
+import { authRoutes } from "./auth";
 import { contentTypes } from "./content-types";
 import { multiHandler } from "./handlers";
 import { HttpCode, httpCodes } from "./http-codes";
@@ -22,6 +23,7 @@ const okText = (result: string): Result => {
 };
 
 const routes: Route[] = [
+    ...authRoutes,
     {
         path: "/slow",
         methods: ["GET"],