Fix CORS origin trimming, unused import, and fragile error handling (FRE-4749)

- P2: Add .map(s => s.trim()) to trim whitespace from comma-separated ALLOWED_ORIGINS
- P3: Remove unused setSentryUser import from @shieldai/monitoring
- P3: Replace fragile string prefix matching with boolean isValidProtocol sentinel

Co-Authored-By: Paperclip <noreply@paperclip.ing>

packages/api/src/index.ts

@@ -8,7 +8,7 @@ import { errorHandlingMiddleware } from './middleware/error-handling.middleware'
 import { loggingMiddleware } from './middleware/logging.middleware';
 import { apiEnv, loggingConfig, getCorsOrigins } from './config/api.config';
 import { routes } from './routes';
-import { initDatadog, initSentry, setSentryUser } from '@shieldai/monitoring';
+import { initDatadog, initSentry } from '@shieldai/monitoring';
 
 const fastify = Fastify({
   logger: loggingConfig,