fix: exclude test files from TypeScript build

Updated tsconfig.json to exclude test files and setup files from the
production build. This resolves TypeScript compilation errors when
building the package, as test files with vitest globals don't need
to be included in the distributed package.

🤖 Generated with [Claude Code](https://claude.ai/code)

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

packages/abacus-react/tsconfig.json

@@ -24,6 +24,8 @@
   "exclude": [
     "node_modules",
     "dist",
-    "**/*.stories.*"
+    "**/*.stories.*",
+    "**/*.test.*",
+    "src/test/**/*"
   ]
 }