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/pages/History.tsx

@@ -0,0 +1,49 @@
+/**
+ * @file History.tsx
+ * @description Tabbed shell for /sessions that hosts the two views over the same
+ * event pipeline: the per-session list and the raw activity feed. The active tab
+ * lives in the `?view=` query param, so `/activity` can redirect into it.
+ * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
+ */
+import type { ComponentType } from "react";
+import { useSearchParams } from "react-router-dom";
+import { useTranslation } from "react-i18next";
+import { Activity, FolderOpen } from "lucide-react";
+import { PageTabs } from "../components/PageTabs";
+import { Sessions } from "./Sessions";
+import { ActivityFeed } from "./ActivityFeed";
+
+interface HistoryView {
+  id: string;
+  label: string;
+  Icon: ComponentType<{ className?: string }>;
+  Panel: ComponentType;
+}
+
+/**
+ * Sessions page shell: grouped sessions and the raw event stream as sibling tabs.
+ * @returns The tab bar plus the active view.
+ */
+export function History() {
+  const { t } = useTranslation("nav");
+  const [params, setParams] = useSearchParams();
+
+  const views: HistoryView[] = [
+    { id: "sessions", label: t("sessions"), Icon: FolderOpen, Panel: Sessions },
+    { id: "events", label: t("activityFeed"), Icon: Activity, Panel: ActivityFeed },
+  ];
+  const defaultView = views[0]!;
+  const active = views.find((v) => v.id === params.get("view")) ?? defaultView;
+
+  return (
+    <div className="space-y-6">
+      <PageTabs
+        ariaLabel={t("sessions")}
+        activeId={active.id}
+        onSelect={(id) => setParams(id === defaultView.id ? {} : { view: id }, { replace: true })}
+        tabs={views.map(({ id, label, Icon }) => ({ id, label, Icon }))}
+      />
+      <active.Panel />
+    </div>
+  );
+}

client/src/pages/SettingsHub.tsx

@@ -7,6 +7,7 @@ import type { ComponentType } from "react";
 import { useSearchParams } from "react-router-dom";
 import { useTranslation } from "react-i18next";
 import { Boxes, Settings as SettingsIcon, SquareTerminal, MousePointerClick } from "lucide-react";
+import { PageTabs } from "../components/PageTabs";
 import { Settings } from "./Settings";
 import { CcConfig } from "./CcConfig";
 
@@ -45,37 +46,17 @@ export function SettingsHub() {
 
   return (
     <div className="space-y-6">
-      <div
-        role="tablist"
-        aria-label={t("tools.label", "Tools")}
-        className="flex items-center gap-1.5 overflow-x-auto no-scrollbar border-b border-border/60 pb-2"
-      >
-        {TOOL_TABS.map(({ id, labelKey, Icon, Panel }) => {
-          const isActive = id === active.id;
-          return (
-            <button
-              key={id}
-              type="button"
-              role="tab"
-              aria-selected={isActive}
-              onClick={() =>
-                setParams(id === DASHBOARD_TAB.id ? {} : { tool: id }, { replace: true })
-              }
-              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" />
-              {t(labelKey)}
-              {!Panel && (
-                <span className="text-[10px] text-fg-muted">{t("tools.soonBadge", "soon")}</span>
-              )}
-            </button>
-          );
-        })}
-      </div>
+      <PageTabs
+        ariaLabel={t("tools.label", "Tools")}
+        activeId={active.id}
+        onSelect={(id) => setParams(id === DASHBOARD_TAB.id ? {} : { tool: id }, { replace: true })}
+        tabs={TOOL_TABS.map(({ id, labelKey, Icon, Panel }) => ({
+          id,
+          Icon,
+          label: t(labelKey),
+          ...(Panel ? {} : { badge: t("tools.soonBadge", "soon") }),
+        }))}
+      />
 
       {active.Panel ? (
         <active.Panel />