perf: use tsgo and parallelize builds, excluding a2a-server

package.json

@@ -106,6 +106,7 @@
     "@types/react-dom": "^19.2.0",
     "@types/shell-quote": "^1.7.5",
     "@types/ws": "^8.18.1",
+    "@typescript/native-preview": "^7.0.0-dev.20260412.1",
     "@vitest/coverage-v8": "^3.1.1",
     "@vitest/eslint-plugin": "^1.3.4",
     "asciichart": "^1.5.25",

scripts/build.js

@@ -23,7 +23,6 @@ if (!existsSync(join(root, 'node_modules'))) {
 const workspaces = [
   '@google/gemini-cli-test-utils',
   '@google/gemini-cli-core',
-  '@google/gemini-cli-a2a-server',
   '@google/gemini-cli',
   'gemini-cli-vscode-ide-companion',
 ];

scripts/build_package.js

@@ -29,7 +29,7 @@ if (!process.cwd().includes('packages')) {
 const packageName = basename(process.cwd());
 
 // build typescript files
-execSync('tsc --build', { stdio: 'inherit' });
+execSync('tsgo --build', { stdio: 'inherit' });
 
 // Run package-specific bundling if the script exists
 const bundleScript = join(process.cwd(), 'scripts', 'bundle-browser-mcp.mjs');