feat(settings): host Claude config as a tab in Settings

Settings becomes a tabbed shell (SettingsHub) with one tab per AI tool:
Dashboard (existing settings), Claude Code (CcConfig), plus Codex and
Cursor placeholders. Active tab lives in the ?tool= query param, and the
old /cc-config route redirects to /settings?tool=claude-code. The
standalone sidebar entry is dropped.

Adding a tool is one entry in TOOL_TABS plus its i18n label.

client/src/App.tsx

@@ -43,8 +43,7 @@
  * - `./pages/SessionDetail`
  * - `./pages/ActivityFeed`
  * - `./pages/Workflows`
- * - `./pages/Settings`
- * - `./pages/CcConfig`
+ * - `./pages/SettingsHub`
  * - `./pages/Workspace`
  *
  * ## Testing pointers
@@ -68,8 +67,7 @@ import { Sessions } from "./pages/Sessions";
 import { SessionDetail } from "./pages/SessionDetail";
 import { ActivityFeed } from "./pages/ActivityFeed";
 import { Workflows } from "./pages/Workflows";
-import { Settings } from "./pages/Settings";
-import { CcConfig } from "./pages/CcConfig";
+import { SettingsHub } from "./pages/SettingsHub";
 import { Workspace } from "./pages/Workspace";
 import { NotFound } from "./pages/NotFound";
 import { useWebSocket } from "./hooks/useWebSocket";
@@ -102,9 +100,12 @@ export default function App() {
             <Route path="activity" element={<ActivityFeed />} />
             <Route path="workflows" element={<Workflows />} />
             <Route path="lanes" element={<Navigate to="/run" replace />} />
-            <Route path="cc-config" element={<CcConfig />} />
+            <Route
+              path="cc-config"
+              element={<Navigate to="/settings?tool=claude-code" replace />}
+            />
             <Route path="run" element={<Workspace />} />
-            <Route path="settings" element={<Settings />} />
+            <Route path="settings" element={<SettingsHub />} />
             <Route path="*" element={<NotFound />} />
           </Route>
         </Routes>