feat: integrate Datadog APM + Sentry error tracking with CloudWatch metrics FRE-4806

- Add CloudWatch metrics emitter (api_latency, api_requests, api_errors)
- Add request monitoring middleware for API (latency, error rate, throughput)
- Register error-handling, logging, and monitoring middleware in server.ts
- Add Datadog log forwarding via HTTP intake API
- Add application-level CloudWatch alarms for P99 latency, error rate, throughput
- Inject Datadog/Sentry env vars and secrets into ECS task definitions
- Add DD_API_KEY and SENTRY_DSN to ECS secrets
- Create CloudWatch log groups for datadog and sentry services
- Update .env.example with AWS_REGION and monitoring variables
- Add @aws-sdk/client-cloudwatch dependency to monitoring package

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

packages/monitoring/src/datadog-logs.ts

@@ -0,0 +1,49 @@
+import { getMonitoringConfig } from './config';
+
+let logForwarder: { send: (log: string, service: string) => Promise<void> } | null = null;
+
+export function initDatadogLogs() {
+  const config = getMonitoringConfig();
+
+  if (!process.env.DD_API_KEY) {
+    console.log('[Datadog Logs] API key not configured, log forwarding disabled');
+    return;
+  }
+
+  const site = process.env.DD_SITE || 'datadoghq.com';
+  const logIntakeUrl = `https://http-intake.logs.${site}`;
+
+  logForwarder = {
+    async send(log: string, service: string) {
+      try {
+        const payload = JSON.stringify({
+          ddsource: 'nodejs',
+          ddtags: `env:${config.DD_ENV},service:${service}`,
+          hostname: config.DD_SERVICE,
+          message: log,
+          service,
+        });
+
+        await fetch(`${logIntakeUrl}/api/v2/logs`, {
+          method: 'POST',
+          headers: {
+            'DD-API-KEY': process.env.DD_API_KEY!,
+            'Content-Type': 'application/json',
+          },
+          body: payload,
+        });
+      } catch (err) {
+        console.warn('[Datadog Logs] Forward failed:', (err as Error).message);
+      }
+    },
+  };
+}
+
+export async function forwardLog(log: string, service: string = 'shieldai-api') {
+  if (!logForwarder) return;
+  await logForwarder.send(log, service);
+}
+
+export function getLogForwarder() {
+  return logForwarder;
+}