feat: 为通用助手市场条目配置透明头像 (#219)

通用助手源仓 PR #2 已发布 1.0.1 的透明头像。本 PR 给 system/repository/listing-only
展示条目增加相同的自包含 `assets/avatar.webp` 与
`avatar.image.path`，更新版本、目录日期和双语更新日志；离线或尚未加载本地 Agent 的市场也能取图，保留字符/渐变回落。

验证：i18n、严格 catalog metadata
完整覆盖、翻译新鲜度均通过（零错误、105条既有警告）；头像与源仓字节一致，512×512、真实alpha，现有运行时透明策略通过。完整公开工作树与协作元数据扫描及语义核读通过，零敏感匹配。主仓
market.zip 后续由正式同步脚本生成，不手改ZIP。

General Assistant source PR #2 published its transparent avatar in
1.0.1. This adds the same self-contained image and avatar reference to
the system/repository/listing-only market entry, updates its
version/catalog date and bilingual changelog, and retains the
character/gradient fallback.

Validation: i18n, complete strict catalog metadata and translation
freshness pass with zero errors and 105 existing warnings. The image is
byte-identical to the source avatar, is 512×512 with genuine alpha, and
passes the runtime transparency policy. Full public-tree and
collaboration metadata scanning and semantic review passed. The client
market ZIP will be generated only by the official sync script.

Source: https://github.com/desirecore/agent-general-assistant/pull/2

agents/general-assistant/agent.json

@@ -3,11 +3,14 @@
   "name": "通用助手",
   "avatar": {
     "t": "助",
-    "bg": "linear-gradient(135deg, #007AFF, #005ECB)"
+    "bg": "linear-gradient(135deg, #007AFF, #005ECB)",
+    "image": {
+      "path": "assets/avatar.webp"
+    }
   },
   "category": "productivity",
-  "version": "1.0.0",
-  "updatedAt": "2026-10-14",
+  "version": "1.0.1",
+  "updatedAt": "2026-10-15",
   "maintainer": {
     "name": "DesireCore Official",
     "verified": true
@@ -67,6 +70,18 @@
     "tools": []
   },
   "changelog": [
+    {
+      "version": "1.0.1",
+      "date": "2026-10-15",
+      "changes": {
+        "zh-CN": [
+          "配置透明背景人物头像，随内置种子与市场自包含分发。"
+        ],
+        "en-US": [
+          "Added a transparent portrait bundled with the Agent seed and marketplace listing."
+        ]
+      }
+    },
     {
       "version": "1.0.0",
       "date": "2026-10-14",

agents/general-assistant/catalog-metadata.v1.json

@@ -33,7 +33,7 @@
   "timestamps": {
     "catalogUpdatedAt": {
       "state": "known",
-      "value": "2026-10-14",
+      "value": "2026-10-15",
       "precision": "day"
     },
     "releasePublishedAt": {