Fix test coverage configuration path

Update vitest config to exclude src/index.ts instead of index.ts
from coverage reports after entry point structure migration.

Author: jdalton

vitest.config.mts

@@ -37,7 +37,7 @@ export default defineConfig({
         'dist/**',
         'scripts/**',
         'test/**',
-        'index.ts',
+        'src/index.ts',
       ],
       all: true,
       thresholds: {