feat: v2.7.8 — Artifacts hub, clone related repos as extra folders, quieter resume prompt

- Artifacts (/artifacts): claude.ai pages sessions publish (captured from the
  Artifact tool's hook), pinned workspace files, skills and plugins, each
  kept as a snapshot; shared ones appear in a Hub and a skill or plugin
  installs into the viewer's own account (server/lib/artifacts.js,
  /api/artifacts, docs/plans/artifacts/).
- Workspace extra folders: clone one or more related repos beside the
  workspace and add them in one step (POST /api/lanes/:id/sources/clone).
- A pane that ended by itself while tmux kept running is no longer offered
  for resume (tmux.serverStartedAt in reconcileOrphans).
- Changes panel: a folder that is not a git repo opens on Files, and its
  files open from there.
- Plus the parallel sessions' work in this tree: File Explorer button in the
  panel header, user delete, RSA SSH keys, chat/terminal and pet fixes.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

client/src/App.tsx

@@ -64,6 +64,7 @@ import { GlobalTooltip } from "./components/Tooltip";
 import { Toaster } from "./components/Toaster";
 import { ConfirmHost } from "./components/ConfirmHost";
 import { RouteErrorBoundary, reloadOnce } from "./components/RouteErrorBoundary";
+import { usePermissions } from "./components/AuthGate";
 import { NotFound } from "./pages/NotFound";
 import { useWebSocket } from "./hooks/useWebSocket";
 import { useNotifications } from "./hooks/useNotifications";
@@ -89,6 +90,7 @@ const SnapshotView = lazy(() =>
 );
 const FilesPage = lazy(() => import("./pages/FilesPage").then((m) => ({ default: m.FilesPage })));
 const Users = lazy(() => import("./pages/Users").then((m) => ({ default: m.Users })));
+const Artifacts = lazy(() => import("./pages/Artifacts").then((m) => ({ default: m.Artifacts })));
 
 function PageFallback() {
   const { t } = useTranslation();
@@ -108,6 +110,11 @@ function Page({ children }: { children: ReactNode }) {
   );
 }
 
+/** A page only a shared server needs (the File Explorer): local mode goes home. */
+function ServerOnly({ children }: { children: ReactNode }) {
+  return usePermissions().local ? <Navigate to="/" replace /> : <>{children}</>;
+}
+
 /** Keyed by the id so moving to another session starts from fresh state. */
 function SessionDetailRoute() {
   const { id } = useParams();
@@ -212,13 +219,23 @@ export default function App() {
               }
             />
             <Route
-              path="files"
+              path="artifacts"
               element={
                 <Page>
-                  <FilesPage />
+                  <Artifacts />
                 </Page>
               }
             />
+            <Route
+              path="files"
+              element={
+                <ServerOnly>
+                  <Page>
+                    <FilesPage />
+                  </Page>
+                </ServerOnly>
+              }
+            />
             <Route
               path="users"
               element={