test(market): delist temporary QA agent (#89)

Removes the temporary QA-only Agent listing after successful real Market
installation verification. The installed local copy is intentionally
verified separately to ensure delisting does not delete user-owned
installations.

manifest.json

@@ -1,6 +1,6 @@
 {
   "name": "DesireCore Official Market",
-  "version": "1.2.27",
+  "version": "1.2.28",
   "schemaVersion": "1.1.0",
   "supportedLocales": ["zh-CN", "en-US"],
   "defaultLocale": "en-US",
@@ -26,7 +26,7 @@
     "url": "https://github.com/desirecore/market.git"
   },
   "stats": {
-    "totalAgents": 2,
+    "totalAgents": 1,
     "totalSkills": 60,
     "lastUpdated": "2026-08-23"
   },