feat(KB-129): dashboard performance optimizations

- Fix SSE hook cleanup to prevent memory leaks and stale connections
- Cap agent log memory and optimize batch log processing
- Memoize Board, Column, and TaskCard with custom comparator to reduce re-renders
- Stabilize column task arrays and preserve pagination across live updates
- Add TaskCardBadge component for PR/issue state display
- Remove deprecated GitHub polling code and archive functionality from core store

packages/dashboard/src/routes.test.ts

@@ -118,6 +118,38 @@ function buildMultipart(fieldName: string, filename: string, contentType: string
   return { body, boundary };
 }
 
+describe("GET /tasks", () => {
+  let store: TaskStore;
+
+  beforeEach(() => {
+    store = createMockStore();
+  });
+
+  function buildApp() {
+    const app = express();
+    app.use(express.json());
+    app.use("/api", createApiRoutes(store));
+    return app;
+  }
+
+  it("returns tasks with optional pagination params", async () => {
+    (store.listTasks as ReturnType<typeof vi.fn>).mockResolvedValueOnce([FAKE_TASK_DETAIL]);
+
+    const res = await GET(buildApp(), "/api/tasks?limit=10&offset=5");
+
+    expect(res.status).toBe(200);
+    expect(res.body).toHaveLength(1);
+    expect(store.listTasks).toHaveBeenCalledWith({ limit: 10, offset: 5 });
+  });
+
+  it("returns 400 for invalid pagination params", async () => {
+    const res = await GET(buildApp(), "/api/tasks?limit=-1");
+
+    expect(res.status).toBe(400);
+    expect(res.body.error).toContain("limit");
+  });
+});
+
 describe("GET /tasks/:id", () => {
   let store: TaskStore;
 

packages/dashboard/src/routes.ts

@@ -582,9 +582,22 @@ export function createApiRoutes(store: TaskStore, options?: ServerOptions): Rout
   registerModelsRoute(router, options?.modelRegistry);
 
   // List all tasks
-  router.get("/tasks", async (_req, res) => {
+  router.get("/tasks", async (req, res) => {
     try {
-      const tasks = await store.listTasks();
+      const limit = typeof req.query.limit === "string" ? Number.parseInt(req.query.limit, 10) : undefined;
+      const offset = typeof req.query.offset === "string" ? Number.parseInt(req.query.offset, 10) : undefined;
+
+      if (limit !== undefined && (!Number.isFinite(limit) || limit < 0)) {
+        res.status(400).json({ error: "limit must be a non-negative integer" });
+        return;
+      }
+
+      if (offset !== undefined && (!Number.isFinite(offset) || offset < 0)) {
+        res.status(400).json({ error: "offset must be a non-negative integer" });
+        return;
+      }
+
+      const tasks = await store.listTasks({ limit, offset });
       res.json(tasks);
     } catch (err: any) {
       res.status(500).json({ error: err.message });