refactor: 重构代理配置并统一插件管理

- 添加新的配置文件以定义多个代理模型及其对应的服务设置。
- 移除旧插件和MCP配置，替换为单一的oh-my-opencode插件

opencode.jsonc

@@ -4,20 +4,7 @@
   "theme": "tokyonight",
   "model": "anthropic-gateway/claude-sonnet-4-5",
   "small_model": "google-gateway/gemini-3-flash",
-  "plugin": [
-    "@tarquinen/opencode-dcp@latest",
-    "@franlol/opencode-md-table-formatter@latest"
-  ],
-  "mcp": {
-    "context7": {
-      "type": "remote",
-      "url": "https://mcp.context7.com/mcp"
-    },
-    "grep-app": {
-      "type": "remote",
-      "url": "https://mcp.grep.app"
-    }
-  },
+  "plugin": ["oh-my-opencode"],
   "provider": {
     "anthropic-gateway": {
       "name": "Anthropic Gateway",