feat(nodejs): add rate limiting and request validation middleware

Rate Limiting:
- Add IP-based rate limiting using express-rate-limit
- Default limit: 100 requests/minute for most endpoints
- High limit: 1000 requests/minute for /metrics endpoint
- Strict limit: 10 requests/minute for sensitive endpoints
- Factory function for custom rate limits
- Proper IPv6 handling with validate option

Request Validation:
- Add comprehensive request validation middleware
- Field presence validation (requireFields)
- Type validation (validateTypes)
- Constraint validation (min, max, pattern, enum)
- URL parameter validation (validateParams)
- Query parameter validation (validateQuery)
- Combined validator factory (validate)

Additional fixes:
- Downgrade uuid from v13 to v9 for CommonJS/Jest compatibility
- Update jest.config.js with transformIgnorePatterns
- Add rate_limiting info to root endpoint response
- Apply validation to cache POST endpoint as example

Author: NormB

reference-apps/nodejs/jest.config.js

@@ -21,5 +21,9 @@ module.exports = {
   },
   setupFilesAfterEnv: ['./tests/setup.js'],
   testTimeout: 10000,
-  verbose: true
+  verbose: true,
+  // Transform ESM packages to CommonJS for Jest
+  transformIgnorePatterns: [
+    'node_modules/(?!(uuid)/)'
+  ]
 };