feat: use ts-morph for robust AST-based schema post-processing

Replace fragile regex-based post-processing with ts-morph AST transforms:

- Add ts-morph dependency for TypeScript AST manipulation
- Refactor all transforms to collect nodes first, then modify (prevents infinite loops)
- Add field-level validation overrides via configuration:
  - AnnotationsSchema.lastModified: z.iso.datetime({ offset: true })
  - RootSchema.uri: z.string().startsWith("file://")
- Improve union-to-enum transform to handle all cases including chained methods

Re-export AnnotationsSchema and RootSchema from generated (now have proper validation).

Total schemas re-exported: 22
Lines saved: ~202 (2600 → 2398)

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

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

Author: ochafik

package-lock.json

@@ -117,7 +117,6 @@
     },
     "devDependencies": {
         "@cfworker/json-schema": "^4.1.1",
-        "ts-to-zod": "^5.1.0",
         "@eslint/js": "^9.39.1",
         "@types/content-type": "^1.1.8",
         "@types/cors": "^2.8.17",
@@ -134,6 +133,8 @@
         "eslint-plugin-n": "^17.23.1",
         "prettier": "3.6.2",
         "supertest": "^7.0.0",
+        "ts-morph": "^27.0.2",
+        "ts-to-zod": "^5.1.0",
         "tsx": "^4.16.5",
         "typescript": "^5.5.4",
         "typescript-eslint": "^8.48.1",