feat(ui): sidebar project tree, status bar and a tabbed workbench for workspaces

The Workspace page's lane strip moves into the sidebar as a project tree:
workspaces grouped by git repository (new GET /api/projects, cached in
memory, POST /api/projects/refresh), untracked worktrees with Adopt, inline
rename, drag/Alt+arrow ordering and a right-click row menu. The selected
workspace is the URL's ?lane=, one shared lane list feeds the tree, the new
bottom status bar and the page. The Changes panel gains an activity bar
(Files / Changes / Sessions, with resume), and split panes get a header.

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

@@ -70,5 +70,10 @@
   "releaseAvailable": "Có {{version}}",
   "devBuild": "Bản dev · trước {{count}} commit",
   "installedNotRunning": "Đã cài {{version}}, chưa chạy",
-  "releaseUnchecked": "Không kiểm tra được bản mới"
+  "releaseUnchecked": "Không kiểm tra được bản mới",
+  "statusBar": {
+    "running": "{{count}} đang chạy",
+    "needYou": "{{count}} cần bạn",
+    "today": "Hôm nay {{cost}}"
+  }
 }