feat(sessions): merge the activity feed into a tab on /sessions

Sessions and Activity Feed are two views of the same event pipeline, so
they now share one page: /sessions renders a tab bar (Sessions | Activity
Feed) with the active view in the ?view= query param, and /activity
redirects to /sessions?view=events. The sidebar entry is dropped.

The tab bar itself moves out of SettingsHub into components/PageTabs so
both hubs share it, and DocumentTitle loses the two branches for paths
that now only redirect.

client/src/components/DocumentTitle.tsx

@@ -24,12 +24,8 @@ export function DocumentTitle() {
     title = `${t("sessions")} · ${sessionId.slice(0, 8)}`;
   } else if (path.startsWith("/sessions")) {
     title = t("sessions");
-  } else if (path.startsWith("/activity")) {
-    title = t("activityFeed");
   } else if (path.startsWith("/workflows")) {
     title = t("workflows");
-  } else if (path.startsWith("/cc-config")) {
-    title = t("ccConfig");
   } else if (path.startsWith("/run")) {
     title = t("run");
   } else if (path.startsWith("/settings")) {

client/src/components/PageTabs.tsx

@@ -0,0 +1,60 @@
+/**
+ * @file PageTabs.tsx
+ * @description Shared top-of-page tab bar used by the pages that merged several
+ * former routes into one (Settings hub, Sessions/Events history). Rendering only -
+ * the owning page keeps the active tab in its own query param.
+ * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
+ */
+import type { ComponentType } from "react";
+
+export interface PageTab {
+  id: string;
+  label: string;
+  Icon: ComponentType<{ className?: string }>;
+  /** Small muted suffix, e.g. "soon" for a tool that is not integrated yet. */
+  badge?: string;
+}
+
+interface PageTabsProps {
+  tabs: PageTab[];
+  activeId: string;
+  onSelect: (id: string) => void;
+  ariaLabel: string;
+}
+
+/**
+ * Horizontal tab strip for a page that hosts several panels.
+ * @param props - Tabs to render, the active tab id, and the selection callback.
+ * @returns The tab bar element.
+ */
+export function PageTabs({ tabs, activeId, onSelect, ariaLabel }: PageTabsProps) {
+  return (
+    <div
+      role="tablist"
+      aria-label={ariaLabel}
+      className="flex items-center gap-1.5 overflow-x-auto no-scrollbar border-b border-border/60 pb-2"
+    >
+      {tabs.map(({ id, label, Icon, badge }) => {
+        const isActive = id === activeId;
+        return (
+          <button
+            key={id}
+            type="button"
+            role="tab"
+            aria-selected={isActive}
+            onClick={() => onSelect(id)}
+            className={`inline-flex items-center gap-1.5 text-xs whitespace-nowrap px-3 py-1.5 rounded-lg border transition-colors flex-shrink-0 ${
+              isActive
+                ? "bg-accent/15 border-accent/30 text-accent"
+                : "border-border text-fg-secondary hover:text-fg-primary hover:bg-surface-3"
+            }`}
+          >
+            <Icon className="w-3.5 h-3.5" />
+            {label}
+            {badge && <span className="text-[10px] text-fg-muted">{badge}</span>}
+          </button>
+        );
+      })}
+    </div>
+  );
+}

client/src/components/Sidebar.tsx

@@ -88,7 +88,6 @@ function isUpdatePayload(x: unknown): x is UpdateStatusPayload {
 const NAV_KEYS = [
   { to: "/", icon: LayoutDashboard, key: "nav:dashboard" },
   { to: "/sessions", icon: FolderOpen, key: "nav:sessions" },
-  { to: "/activity", icon: Activity, key: "nav:activityFeed" },
   { to: "/workflows", icon: Workflow, key: "nav:workflows" },
   { to: "/run", icon: Play, key: "nav:workspace" },
   { to: "/settings", icon: Settings, key: "nav:settings" },

client/src/components/__tests__/Sidebar.test.tsx

@@ -33,7 +33,10 @@ describe("Sidebar", () => {
     renderSidebar(true);
     expect(screen.getByText("Dashboard")).toBeInTheDocument();
     expect(screen.getByText("Sessions")).toBeInTheDocument();
-    expect(screen.getByText("Activity Feed")).toBeInTheDocument();
+    // Activity Feed and Claude Config are no longer top-level entries: they
+    // moved into tabs on /sessions and /settings respectively.
+    expect(screen.getByText("Settings")).toBeInTheDocument();
+    expect(screen.queryByText("Activity Feed")).toBeNull();
   });
 
   it('should show "Live" when WebSocket is connected', () => {
@@ -60,7 +63,8 @@ describe("Sidebar", () => {
     const hrefs = links.map((link) => link.getAttribute("href"));
     expect(hrefs).toContain("/");
     expect(hrefs).toContain("/sessions");
-    expect(hrefs).toContain("/activity");
+    expect(hrefs).toContain("/settings");
+    expect(hrefs).not.toContain("/activity");
   });
 
   it("should render both language options in expanded mode", () => {