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/agent/vitest.config.ts

@@ -9,6 +9,8 @@ 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",
 	},
 	resolve: {
 		alias: [