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>

bin/agenthub.js

@@ -4232,7 +4232,7 @@ async function cmdCodexAccounts(sub, name, flags) {
   }
   pool.resetQuota();
   table(
-    ["codex account", "kind", "live", "$ 5h", "$ 7d", "quota", "state"],
+    ["codex account", "kind", "live", "$ 5h", "$ 7d", "tok 5h", "tok 7d", "quota", "state"],
     pool
       .poolStatus()
       .map((a) => [
@@ -4241,6 +4241,8 @@ async function cmdCodexAccounts(sub, name, flags) {
         a.livePanes,
         a.spend5h.toFixed(2),
         a.spend7d.toFixed(2),
+        a.tokens5h,
+        a.tokens7d,
         a.quota
           ? a.quota.windows.map((w) => `${w.label} ${Math.round(w.usedPercent)}%`).join(" ")
           : "–",
@@ -4281,7 +4283,7 @@ async function cmdAccounts(sub, positional, flags = {}) {
     await pool.refreshQuotas({ force: true });
     const pct = (w) => (w?.utilization != null ? `${Math.round(w.utilization)}%` : "–");
     table(
-      ["account", "live", "$ 5h", "$ 7d", "quota 5h", "quota wk", "state"],
+      ["account", "live", "$ 5h", "$ 7d", "tok 5h", "tok 7d", "quota 5h", "quota wk", "state"],
       pool
         .poolStatus()
         .map((a) => [
@@ -4289,6 +4291,8 @@ async function cmdAccounts(sub, positional, flags = {}) {
           a.livePanes,
           a.spend5h.toFixed(2),
           a.spend7d.toFixed(2),
+          a.tokens5h,
+          a.tokens7d,
           pct(a.quota?.fiveHour),
           pct(a.quota?.sevenDay),
           a.expired