test(e2e): stubbed /activity feed scenarios (auth bypass)

frontend/cypress/e2e/activity_feed.cy.ts

@@ -0,0 +1,94 @@
+describe("/activity feed", () => {
+  const apiBase = "**/api/v1";
+
+  function stubStreamEmpty() {
+    // Return a minimal SSE response that ends immediately.
+    cy.intercept(
+      "GET",
+      `${apiBase}/activity/task-comments/stream*`,
+      {
+        statusCode: 200,
+        headers: {
+          "content-type": "text/event-stream",
+        },
+        body: "",
+      },
+    ).as("activityStream");
+  }
+
+  it("happy path: renders task comment cards", () => {
+    cy.intercept("GET", `${apiBase}/activity/task-comments*`, {
+      statusCode: 200,
+      body: {
+        items: [
+          {
+            id: "c1",
+            message: "Hello world",
+            agent_name: "Kunal",
+            agent_role: "QA 2",
+            board_id: "b1",
+            board_name: "Testing",
+            task_id: "t1",
+            task_title: "CI hardening",
+            created_at: "2026-02-07T00:00:00Z",
+          },
+          {
+            id: "c2",
+            message: "Second comment",
+            agent_name: "Riya",
+            agent_role: "QA",
+            board_id: "b1",
+            board_name: "Testing",
+            task_id: "t2",
+            task_title: "Coverage policy",
+            created_at: "2026-02-07T00:01:00Z",
+          },
+        ],
+      },
+    }).as("activityList");
+
+    stubStreamEmpty();
+
+    cy.visit("/activity", {
+      onBeforeLoad(win) {
+        win.localStorage.clear();
+      },
+    });
+
+    cy.wait("@activityList");
+
+    cy.contains(/live feed/i).should("be.visible");
+    cy.contains("CI hardening").should("be.visible");
+    cy.contains("Coverage policy").should("be.visible");
+    cy.contains("Hello world").should("be.visible");
+  });
+
+  it("empty state: shows waiting message when no items", () => {
+    cy.intercept("GET", `${apiBase}/activity/task-comments*`, {
+      statusCode: 200,
+      body: { items: [] },
+    }).as("activityList");
+
+    stubStreamEmpty();
+
+    cy.visit("/activity");
+    cy.wait("@activityList");
+
+    cy.contains(/waiting for new comments/i).should("be.visible");
+  });
+
+  it("error state: shows failure UI when API errors", () => {
+    cy.intercept("GET", `${apiBase}/activity/task-comments*`, {
+      statusCode: 500,
+      body: { detail: "boom" },
+    }).as("activityList");
+
+    stubStreamEmpty();
+
+    cy.visit("/activity");
+    cy.wait("@activityList");
+
+    // UI uses query.error.message or fallback.
+    cy.contains(/unable to load feed|boom/i).should("be.visible");
+  });
+});