fix(.claude-plugin): 恢复 marketplace.json source 为本地引用格式

source 改回 "./"，与 1.6.2-beta 保持一致，避免影响用户安装。
远端 marketplace 仓库独立维护带 url/ref 的格式。

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: arch-team

.claude-plugin/marketplace.json

@@ -9,10 +9,7 @@
       "name": "devpace",
       "description": "Never re-explain your project to Claude again. devpace remembers context across sessions, manages requirement changes, and ensures quality gates — all automatically. Zero setup friction, just /pace-init and start coding.",
       "version": "1.6.3",
-      "source": {
-        "url": "https://github.com/arch-team/devpace",
-        "ref": "v1.6.3"
-      },
+      "source": "./",
       "author": {
         "name": "paceforge"
       }