Fix dd-trace init timing in index.ts (FRE-4806)

Import datadog-init as first module to ensure dd-trace .init()
runs before any other imports, fixing P1 auto-instrumentation issue.
Removed redundant manual initDatadog/initSentry calls since
datadog-init.ts already invokes all three init functions.

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

packages/api/src/index.ts

@@ -1,3 +1,5 @@
+// dd-trace must be initialized before any other module is loaded for auto-instrumentation
+import '@shieldai/monitoring/datadog-init';
 import Fastify from 'fastify';
 import cors from '@fastify/cors';
 import helmet from '@fastify/helmet';
@@ -8,7 +10,6 @@ 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 } from '@shieldai/monitoring';
 
 const fastify = Fastify({
   logger: loggingConfig,
@@ -16,10 +17,6 @@ const fastify = Fastify({
   maxParamLength: 500,
 });
 
-// Initialize monitoring (must be first import for auto-instrumentation)
-initDatadog();
-initSentry();
-
 // Register plugins
 async function registerPlugins() {
   // CORS configuration