feat: 统一 apps/mcp/services 为 entries/ Skill 格式

将 20 个条目从三个分散目录（apps/8、mcp/7、services/5）迁移到统一的
entries/ 目录。每个条目包含：
- manifest.json：极简结构化元数据
- install.md：自然语言安装说明（如适用）
- usage.md：自然语言使用说明和连接配置

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

entries/dify/manifest.json

@@ -0,0 +1,21 @@
+{
+  "id": "dify",
+  "name": "Dify",
+  "type": "docker-app",
+  "version": "0.8.3",
+  "author": "Dify.AI",
+  "description": "开源 AI 应用开发平台，支持 RAG、Agent、工作流编排",
+  "tags": [
+    "LLM",
+    "RAG",
+    "Agent",
+    "Workflow"
+  ],
+  "icon": "linear-gradient(135deg, #1C64F2, #7C3AED)",
+  "iconLetter": "D",
+  "platformSupport": [
+    "macos",
+    "windows",
+    "linux"
+  ]
+}