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/components/lanes/FileExplorer.tsx

@@ -270,9 +270,13 @@ export function FileBrowser({
   const folderInput = useRef<HTMLInputElement>(null);
   const ctx = useContextMenu<FsEntry | null>();
 
-  // A new caller target (another workspace's Files tab, the page's URL).
+  // A new caller target (another workspace's Files tab, the page's URL) —
+  // not the echo of our own `go()` through the page's URL, which would wipe
+  // Back's history on every folder opened.
   useEffect(() => {
-    setTarget(placeOf());
+    const next = placeOf();
+    if (samePlace(next, target) && initialPath === path) return;
+    setTarget(next);
     setPathState(initialPath);
     setHistory({ back: [], fwd: [] });
     setSelected(new Set());
@@ -1145,7 +1149,13 @@ export function FileBrowser({
             {listing && !entries.length && !creating && !error && (
               <div className="flex flex-col items-center justify-center gap-2 py-16 text-fg-muted">
                 <Folder className="h-16 w-16 opacity-40" />
-                <p className="text-sm">{query ? t("fx.noMatch") : t("fx.empty")}</p>
+                <p className="max-w-md text-center text-sm">
+                  {query
+                    ? t("fx.noMatch")
+                    : isHomePlace(target) && !path
+                      ? t("fx.homeEmpty")
+                      : t("fx.empty")}
+                </p>
               </div>
             )}
             {loading && !listing && <p className="p-6 text-sm text-fg-muted">{t("fx.loading")}</p>}