fix: v2.6.1 — panes start in their folder again after an update (#69), Changes panel stacks every repo, clickable paths in chat

- #69: tmux applies a pane's `-c` only while its server's own cwd exists.
  The server was forked from the dashboard's cwd (the plugin cache dir),
  outlives updates, and the old cache dir is pruned — after that every new
  pane started in a deleted directory, where `claude` died at once ("run not
  found") and a shell printed getcwd errors. tmux calls now run from `/`,
  and the pane's sh wrapper cds into its folder itself, which also heals a
  tmux server that is already stuck.
- Changes panel: a workspace's extra folders are sections stacked under the
  workspace folder (VS Code Source Control style), with Close repository /
  Close other repositories on a header's right-click.
- Chat: URLs and absolute paths are links; Claude Code's `[Image: source:]`
  line folds into its turn; uploads under `<data dir>/drops/` are listed.
- Update check: a checkout holding commits a newer release lacks reports
  `diverged_from_release` instead of offering a fast-forward that can only fail.

client/src/i18n/locales/en/lanes.json

@@ -48,6 +48,8 @@
   "changes.bin": "bin",
   "changes.binary": "Binary file — not shown.",
   "changes.collapse": "Collapse the changes panel",
+  "changes.closeRepo": "Close repository",
+  "changes.closeOtherRepos": "Close other repositories",
   "changes.collapseAll": "Collapse every file",
   "changes.collapseAllFolders": "Collapse all folders",
   "changes.collapseContext": "Show fewer surrounding lines",
@@ -295,7 +297,6 @@
   "menu.remove": "Delete workspace…",
   "panel.changes": "Changes",
   "panel.analyst": "Analyst",
-  "panel.folder": "Folder to show changes for",
   "replay.placeholder": "Message to continue this session…",
   "replay.hint": "Sending resumes the session in a free pane.",
   "replay.send": "Send",

client/src/i18n/locales/vi/lanes.json

@@ -48,6 +48,8 @@
   "changes.bin": "bin",
   "changes.binary": "File nhị phân — không hiển thị.",
   "changes.collapse": "Thu gọn bảng thay đổi",
+  "changes.closeRepo": "Đóng repository",
+  "changes.closeOtherRepos": "Đóng các repository khác",
   "changes.collapseAll": "Thu gọn tất cả file",
   "changes.collapseAllFolders": "Thu gọn tất cả thư mục",
   "changes.collapseContext": "Bớt dòng xung quanh",
@@ -295,7 +297,6 @@
   "menu.remove": "Xóa workspace…",
   "panel.changes": "Thay đổi",
   "panel.analyst": "Analyst",
-  "panel.folder": "Thư mục để xem thay đổi",
   "replay.placeholder": "Nhắn để tiếp tục session này…",
   "replay.hint": "Gửi tin sẽ resume session trong một pane trống.",
   "replay.send": "Gửi",