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>

client/src/components/run/__tests__/PaneGrid.test.ts

@@ -2,12 +2,13 @@
  * @file PaneGrid.test.ts
  * @description The pane drop preview: it draws where the dragged pane will
  * actually land (`dropPreview` over `applyDrop`), not half of the target's
- * current box, and nothing for a drop that changes nothing.
+ * current box, and nothing for a drop that changes nothing; and the label
+ * naming what a drop does (`dropAction`).
  * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
  */
 
 import { describe, expect, it } from "vitest";
-import { dropPreview } from "../PaneGrid";
+import { dropAction, dropPreview } from "../PaneGrid";
 import { pane, split, type PaneLayout } from "../../../lib/paneLayout";
 
 const AB: PaneLayout = { root: split("row", pane(0), pane(1)), focus: 0 };
@@ -34,3 +35,15 @@ describe("dropPreview", () => {
     expect(dropPreview(full, 5, 0, "left")).toBeNull();
   });
 });
+
+describe("dropAction", () => {
+  it("an edge places the pane on that side", () => {
+    expect(dropAction(AB, 0, "left")).toBe("panes.drop.left");
+    expect(dropAction(AB, 2, "bottom")).toBe("panes.drop.bottom");
+  });
+
+  it("the center swaps a shown pane, or shows one from another tab in its place", () => {
+    expect(dropAction(AB, 0, "center")).toBe("panes.drop.swap");
+    expect(dropAction(AB, 2, "center")).toBe("panes.drop.replace");
+  });
+});