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/pages/Workspace.tsx

@@ -64,12 +64,14 @@ import {
   PanelLeftClose,
   PanelRightClose,
   Maximize2,
+  FolderOpen,
   Minimize2,
   ChartColumn,
   ChevronDown,
   ChevronRight,
 } from "lucide-react";
 import { api } from "../lib/api";
+import { usePermissions } from "../components/AuthGate";
 import type {
   CwdSuggestion,
   LaneSource,
@@ -130,6 +132,7 @@ import PipelineMap from "../components/lanes/PipelineMap";
 import LaneCard, { since } from "../components/lanes/LaneCard";
 import { AddLaneModal } from "../components/lanes/AddLaneModal";
 import { LaneChangesPanel } from "../components/lanes/LaneChangesPanel";
+import { FileExplorer } from "../components/lanes/FileExplorer";
 import { WorkspaceContext } from "../components/lanes/WorkspaceContext";
 import { OPEN_IN_CHANGES_EVENT, type OpenInChanges } from "../lib/openInChanges";
 import { LaneGitRailCounts } from "../components/lanes/LaneGitHeader";
@@ -659,6 +662,7 @@ function ConsoleArea({
 
 export function Workspace() {
   const { t: tLanes } = useTranslation("lanes");
+  const { local } = usePermissions();
   const [searchParams, setSearchParams] = useSearchParams();
 
   // Lane state: the list is the shared store the sidebar reads too; the
@@ -773,6 +777,10 @@ export function Workspace() {
   // Whether the Changes panel is open. A viewer preference, so it lives in
   // localStorage and never reaches the server — same rule as the lane strip's
   // order (client/src/lib/laneOrderStorage.ts).
+  // The File Explorer dialog, opened from the Changes panel header.
+  const [explorerOpen, setExplorerOpen] = useState(false);
+  // Bumped when the File Explorer changed files: the Files tree reads again.
+  const [filesChanged, setFilesChanged] = useState(0);
   const [changesOpen, setChangesOpen] = useState(() => {
     try {
       return window.localStorage.getItem(CHANGES_OPEN_KEY) === "1";
@@ -1511,6 +1519,35 @@ export function Workspace() {
                   >
                     <ChartColumn className="h-4 w-4" />
                   </button>
+                  {/* The File Explorer, beside the window controls — on this
+                      workspace (the session's own worktree when it has one).
+                      Not in local mode: the desktop's file manager is there. */}
+                  {local ? (
+                    <span className="ml-auto" />
+                  ) : (
+                    <>
+                      <button
+                        type="button"
+                        data-testid="panel-file-explorer"
+                        disabled={!panelAt}
+                        onClick={() => setExplorerOpen(true)}
+                        aria-label={tLanes("changes.openExplorer")}
+                        title={tLanes("changes.openExplorer")}
+                        className="ml-auto flex h-6 w-6 items-center justify-center rounded-md text-fg-muted transition-colors hover:bg-surface-4 hover:text-fg-primary disabled:opacity-40"
+                      >
+                        <FolderOpen className="h-4 w-4" />
+                      </button>
+                      {panelAt && (
+                        <FileExplorer
+                          open={explorerOpen}
+                          laneId={panelAt.laneId}
+                          session={panelAt.session}
+                          onChanged={() => setFilesChanged((n) => n + 1)}
+                          onClose={() => setExplorerOpen(false)}
+                        />
+                      )}
+                    </>
+                  )}
                   {/* A window's two controls: Full screen (Restore at full
                       screen, to the last dragged width) and Collapse. */}
                   <button
@@ -1519,7 +1556,7 @@ export function Workspace() {
                     onClick={() => setChangesSize(changesFull ? lastDraggedChanges() : "full")}
                     aria-label={changesSizeLabel}
                     title={changesSizeLabel}
-                    className="ml-auto flex h-6 w-6 items-center justify-center rounded-md text-fg-muted transition-colors hover:bg-surface-4 hover:text-fg-primary"
+                    className="flex h-6 w-6 items-center justify-center rounded-md text-fg-muted transition-colors hover:bg-surface-4 hover:text-fg-primary"
                   >
                     {changesFull ? (
                       <Minimize2 className="h-4 w-4" />
@@ -1568,6 +1605,7 @@ export function Workspace() {
                           wide={changesRatio(changesSize) >= 0.45}
                           onDirtyChange={dirtyFor(key)}
                           openRequest={source ? null : changesRequest}
+                          filesChanged={source ? 0 : filesChanged}
                           // A sibling worktree forks from the lane's SOURCE repo
                           // when it has one (this lane is itself a worktree of
                           // it); an adopted lane is its own repo.