fix: exclude test files from TypeScript type checking

Test files use .ts extensions in imports for Node's native test runner
compatibility, which conflicts with TypeScript's default behavior.
Excluding test files from tsconfig allows tests to run with Node while
maintaining strict type checking for the main codebase.

Co-authored-by: factory-droid[bot] <138933559+factory-droid[bot]@users.noreply.github.com>

web/tsconfig.json

@@ -38,5 +38,5 @@
     "**/*.js",
     ".next/types/**/*.ts"
   ],
-  "exclude": ["node_modules"]
+  "exclude": ["node_modules", "tests/**/*.test.ts"]
 }