test: use quiet dot reporters and show output only for failing tests

Switch vitest packages (ai, agent, coding-agent) to the dot reporter
with silent: passed-only so passing tests stay quiet while failing
tests still print their console output and full diffs. Add the
github-actions reporter on CI for inline annotations. Switch the tui
node:test runner to the dot reporter as well.

packages/ai/vitest.config.ts

@@ -5,5 +5,7 @@ export default defineConfig({
     globals: true,
     environment: 'node',
     testTimeout: 30000, // 30 seconds for API calls
+    reporters: process.env.GITHUB_ACTIONS ? ['dot', 'github-actions'] : ['dot'],
+    silent: 'passed-only',
   }
 });