fix: exclude test files from the tsc build output

Compiled .test.js files were ending up in dist/ and vitest was
picking those up too, doubling every test run.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

apps/server/tsconfig.json

@@ -9,5 +9,6 @@
     "esModuleInterop": true,
     "skipLibCheck": true
   },
-  "include": ["src"]
+  "include": ["src"],
+  "exclude": ["src/**/*.test.ts"]
 }