Expand vitest include glob to cover client lib tests

Widen the test include pattern from 'src/client/components/**/*.test.tsx'
to 'src/client/**/*.test.{ts,tsx}' so that tests in src/client/lib/ (e.g.
markdown.test.ts) are discovered automatically.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

vitest.config.ts

@@ -12,7 +12,7 @@ export default defineConfig({
     environment: "node",
     include: [
       "tests/unit/**/*.test.ts",
-      "src/client/components/**/*.test.tsx",
+      "src/client/**/*.test.{ts,tsx}",
     ],
   },
 });