fix: preserve activity errors, asset bytes and runner summaries

Treat non-2xx activity responses as feed errors, preserve non-Markdown Copilot agent assets, and apply the reviewed reference escape parity correction with regenerated bindings. Allow the test runner to drain piped output on its existing success or failure exit status. Validate installed workflows and bounded real Node20/24 pipe regressions.

tests/scripts/dashboard-web.test.js

@@ -58,6 +58,68 @@ test('renderHTML emits executable scripts without syntax errors', () => {
   for (const script of scripts) new vm.Script(script[1]);
 });
 
+asyncTest('served activity UI shows HTTP failures as errors and preserves healthy empty and populated feeds', async () => {
+  const dir = createTempDir('ecc-activity-response-');
+  const savedDataHome = process.env.ECC_AGENT_DATA_HOME;
+  const originalClose = fs.closeSync;
+  try {
+    process.env.ECC_AGENT_DATA_HOME = dir;
+    const log = path.join(dir, 'metrics', 'tool-usage.jsonl');
+    writeFile(dir, 'metrics/tool-usage.jsonl', '');
+    const reported = [];
+    await withDashboardServer(async port => {
+      const page = await requestDashboard(port);
+      assert.strictEqual(page.statusCode, 200);
+      const script = [...page.body.matchAll(/<script>([\s\S]*?)<\/script>/g)]
+        .find(match => match[1].includes('function renderActivity()'))[1];
+      async function renderFeed() {
+        let status;
+        let jsonReads = 0;
+        const html = await new Promise((resolve, reject) => {
+          const timeout = setTimeout(() => reject(new Error('Activity UI did not render')), REQUEST_TIMEOUT_MS);
+          const panel = { set innerHTML(value) { clearTimeout(timeout); resolve(value); } };
+          const context = vm.createContext({
+            document: { getElementById: () => panel, createElement: () => ({}), head: { appendChild() {} } },
+            window: { showTab() {} }, setInterval() {}, clearInterval() {},
+            fetch: async url => {
+              const response = await fetch(`http://127.0.0.1:${port}${url}`);
+              status = response.status;
+              return { ok: response.ok, json() { jsonReads++; return response.json(); } };
+            },
+          });
+          new vm.Script(script).runInContext(context);
+          context.window.showTab('activity');
+        });
+        return { html, status, jsonReads };
+      }
+      // A descriptor-close failure escapes loadActivity's read catch and drives
+      // the real server's generic HTTP 500 response without leaking its detail.
+      fs.closeSync = fd => { originalClose(fd); throw new Error('private close detail'); };
+      const failed = await renderFeed();
+      fs.closeSync = originalClose;
+      assert.strictEqual(failed.status, 500);
+      assert.match(failed.html, /Could not load activity feed/);
+      assert.doesNotMatch(failed.html, /No recorded tool calls|private close detail/);
+      assert.strictEqual(failed.jsonReads, 0);
+      assert.strictEqual(reported.length, 1);
+      const empty = await renderFeed();
+      assert.strictEqual(empty.status, 200);
+      assert.match(empty.html, /No recorded tool calls yet/);
+      assert.strictEqual(empty.jsonReads, 1);
+      fs.writeFileSync(log, JSON.stringify({ session_id: 'response-fixture', tool_name: 'Read', input_summary: 'visible activity' }) + '\n');
+      const populated = await renderFeed();
+      assert.strictEqual(populated.status, 200);
+      assert.match(populated.html, /visible activity/);
+      assert.doesNotMatch(populated.html, /Could not load activity feed|No recorded tool calls/);
+    }, { reportError: (message, error) => reported.push({ message, error }) });
+  } finally {
+    fs.closeSync = originalClose;
+    if (savedDataHome === undefined) delete process.env.ECC_AGENT_DATA_HOME;
+    else process.env.ECC_AGENT_DATA_HOME = savedDataHome;
+    cleanup(dir);
+  }
+});
+
 test('activity loading bounds large logs and ignores malformed rows', () => {
   const { loadActivity } = require(SCRIPT);
   withTempDir('ecc-activity-', dir => {