chore: v2.8.24 — sub-agent edits in Edited N files, OpenCode/Grok dropped, Artifacts list view and skill sync

Edited N files (#86): a turn's card counts the files its subagents wrote
or edited (read from their own transcripts, nested ones folded in), and a
turn longer than the chat's first page keeps the edits made before the
page cut. A non-Claude transcript page honours its limit again.

AI tools: OpenCode and Grok Build left the catalog (opencode-usage.js
gone; a Grok payload on the Claude hook route is dropped), and so did the
leftover Kimi Code quota reader.

Artifacts: a list view, skill packs and badges only by exception; a
shared skill follows its owner's folder, and an installer whose copy
differs is offered Update.

package.json

@@ -1,6 +1,6 @@
 {
   "name": "agenthub",
-  "version": "2.8.23",
+  "version": "2.8.24",
   "bin": {
     "agenthub": "bin/agenthub.js"
   },