feat: workspace aliases, tab groups of split panes, native path picker (v2.1.0)

- /api/workspaces and `agenthub workspace(s)` / `--workspace` as aliases of
  /api/lanes and `agenthub lanes` / `--lane`; old names print one stderr note.
  REPL `help lanes|workspace|workspaces` resolves through the aliases.
- A workspace holds up to ten sessions (slots 0-9); every console tab is a
  group of 1-4 split panes (PaneGroups, agenthub.workspace.paneLayout);
  parseGroups keeps the stored active tab when an earlier one is dropped.
- Browse button beside path fields: POST /api/lanes/pick-path opens the OS
  picker on the server's desktop — loopback only and no forwarding header
  (EREMOTE), a display failure is ENODIALOG not a Cancel, the dialog is
  killed when the request closes, a folder field falls back to the in-app
  browser on any failure.
- Changes rail counts chip, image viewer (/git/raw), status bar session
  counts and per-day cost (`date=` on /api/pricing/cost).
- /agenthub-open and /agenthub-doctor run from the INSTALLED build
  (supersededBy), doctor offers fixes behind two confirmations; plugin-open
  treats a locked bootstrap as non-fatal.
- New-terminal shell waits for the first attach (issue #55).
- repo-onboarding / debug-live-issue skills removed.
- OpenAPI: pick-path, lane/date on /pricing/cost, tool on /run/history,
  /api/workspaces mount.

plugins/agenthub/commands/agenthub-open.md

@@ -1,14 +1,23 @@
 ---
-description: Rebuild the dashboard UI and print its URL
+description: Rebuild the dashboard UI and print its URL — runs the doctor when it fails
 ---
 
 Rebuild the dashboard bundle, then print the URL. Always forces a rebuild so a
 stale bundle (e.g. after a fix commit landed but the bootstrap's build predates
 it) never serves silently. Also finishes the build if the bootstrap's own
-attempt failed (check `~/.claude/agenthub/runtime/client-build.log`).
+attempt failed (check `client-build.log` in the runtime dir — `<data dir>/runtime`,
+by default `~/.claude/agenthub/runtime`).
+
+Run it from the plugin build that is installed NOW, as ONE command so `ROOT`
+survives — a session not restarted after an update still names the old build
+in `${CLAUDE_PLUGIN_ROOT}`, whose bootstrap refuses to run (`superseded`) and
+whose client would be built over the new one:
 
 ```bash
-node "${CLAUDE_PLUGIN_ROOT}/scripts/plugin-open.js" --force
+ROOT=$(node -e 'console.log(require(process.argv[1]).supersededBy() || "")' \
+  "${CLAUDE_PLUGIN_ROOT}/scripts/plugin-bootstrap.js")
+ROOT="${ROOT:-${CLAUDE_PLUGIN_ROOT}}"
+node "$ROOT/scripts/plugin-open.js" --force
 ```
 
 Install + build takes a few minutes if the client toolchain isn't already
@@ -19,7 +28,14 @@ re-runs bootstrap first and prints `Server restarted on the current plugin
 version.` (without it, the fresh bundle would call routes that old server
 never had).
 
-Then help the user open it:
+**If it exits non-zero** (a failed build, or a bootstrap that did not bring the
+server up): quote its error line, say you are running the doctor, then read
+`$ROOT/plugins/agenthub/commands/agenthub-doctor.md` (the `ROOT` resolved above)
+and follow it from step 1 — diagnose, offer to fix, show the plan, fix only what
+the user approves. After the fixes, run the `plugin-open.js --force` command
+above once more; if it fails again, report its error and stop.
+
+On success, help the user open the URL:
 
 ```bash
 uname -s