feat: add users and templates routes, enhance existing API routes

New routes:
- GET /users — list all users
- GET/POST /templates — list and create templates
- PATCH /templates/:id — update template
- POST /templates/preview — render template with ticket/demo context

Enhanced routes:
- tickets: custom field support on create, status classification helper
- custom-fields: PATCH endpoint, auto-generate short key from name
- lifecycles: PATCH endpoint
- queues: PATCH endpoint

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/routes/users.ts

@@ -0,0 +1,17 @@
+import { Hono } from 'hono';
+import { asc } from 'drizzle-orm';
+import type { Db } from '../db/index.ts';
+import { users } from '../db/schema.ts';
+
+export function createUsersRouter(db: Db): Hono {
+  const router = new Hono();
+
+  router.get('/', async (c) => {
+    const result = await db.query.users.findMany({
+      orderBy: asc(users.username),
+    });
+    return c.json(result);
+  });
+
+  return router;
+}