feat: add infrastructure foundation — scripts, schema key, new routes, model fields

- Add npm scripts for dev, migrate, seed, smoke
- Add key column to scrips table (unique short identifier)
- Register users and templates routes in server
- Set development: false in Bun.serve for production mode
- Add description and custom_fields to CreateTicketSchema
- Make owner_id nullable/optional for unassigned tickets
- Add migration for custom field key column

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

package.json

@@ -3,6 +3,13 @@
   "module": "src/index.ts",
   "type": "module",
   "private": true,
+  "scripts": {
+    "dev:backend": "bun run src/index.ts",
+    "db:migrate": "bun run src/db/migrate.ts",
+    "db:seed": "bun run src/db/seed.ts",
+    "db:seed:reset": "bun run src/db/seed.ts --reset",
+    "smoke": "bun run scripts/smoke-test.ts"
+  },
   "devDependencies": {
     "@types/bun": "latest",
     "@types/handlebars": "^4.1.0",