Add vitest config to prevent deploy side-effect (#44)

* Initial plan

* Decouple build from lint/test to avoid deploy on validation

Co-authored-by: cyanzhong <6745066+cyanzhong@users.noreply.github.com>

* Add vitest.config.mts to prevent deploy side-effect during tests

Co-authored-by: cyanzhong <6745066+cyanzhong@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: cyanzhong <6745066+cyanzhong@users.noreply.github.com>

Author: Copilot

vitest.config.mts

@@ -0,0 +1,8 @@
+import { defineConfig } from 'vitest/config';
+import mainPackage from './package.json' with { type: 'json' };
+
+export default defineConfig({
+  define: {
+    __PKG_VERSION__: JSON.stringify(mainPackage.version),
+  },
+});