feat: track infralens scan completions via vercel analytics

- fire a custom "infralens_scan_completed" event from the run-checks
  server action on successful scans, to distinguish real tool usage
  from page views in web analytics

Author: Randy-R-code

app/tools/infralens/actions/run-checks.ts

@@ -9,6 +9,7 @@ import { logWarn } from "@infralens-lib/log";
 import { isSecurityError } from "@infralens-lib/security/errors";
 import { resolveValidatedTarget } from "@infralens-lib/security/resolve-target";
 import { normalizeTarget } from "@infralens-lib/security/target";
+import { track } from "@vercel/analytics/server";
 import { headers } from "next/headers";
 
 // Returned instead of thrown for every expected rejection (rate limit,
@@ -72,5 +73,7 @@ export async function runInfraChecks(
     timeout: CHECK_TIMEOUT_MS,
   });
 
+  await track("infralens_scan_completed");
+
   return { ok: true, data: response };
 }