feat: v2.8.0 — Artifacts uploads and plugin links, console tab combos, account avatars

- Artifacts hub: upload a file from the computer; make a skill by uploading a
  Markdown file, files, a folder or a .zip/.skill, or by writing it in the
  dialog; add plugins by picking from the list a marketplace link answers
  (POST /api/artifacts/plugin/inspect); Settings → AI tools → Artifacts Hub.
- Console tabs are combos of up to four split panes (ConsoleTabs, PaneGrid).
- Accounts: an own avatar (PUT/DELETE /api/me/avatar, raster only, ≤ 1 MB,
  <data dir>/avatars/), shown with name and role at the sidebar's foot and on
  the workspace owner groups (GET /api/users/:id/avatar, owner_avatar_at).
- Users page: per-user storage (GET /api/users/storage, measured in a worker)
  and account-pool spend/tokens per account (server/lib/pool-usage.js).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "agenthub",
-  "version": "2.7.9",
+  "version": "2.8.0",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "agenthub",
-      "version": "2.7.9",
+      "version": "2.8.0",
       "hasInstallScript": true,
       "license": "UNLICENSED",
       "dependencies": {