refactor: full typescript migration (#174)

vitest.config.ts

@@ -0,0 +1,32 @@
+import { defineConfig } from "vitest/config";
+
+export default defineConfig({
+  test: {
+    // Run tests in Node environment
+    environment: "node",
+
+    // Test file patterns
+    include: ["tests/**/*.test.ts"],
+
+    // Coverage configuration
+    coverage: {
+      provider: "v8",
+      reporter: ["text", "json", "html"],
+      include: ["src/**/*.ts"],
+      exclude: [
+        "src/generated/**",
+        "src/**/*.d.ts",
+        "**/*.test.ts",
+        "scripts/**",
+      ],
+    },
+
+    // Timeout for integration tests (some may be slow)
+    testTimeout: 30000,
+
+    // Vitest 4: avoid forks on macOS (can produce kill EPERM on teardown) and
+    // keep files sequential to reduce contention around Hugo + temp dirs.
+    pool: "threads",
+    fileParallelism: false,
+  },
+});