Refactor plugin system: update JSON schema, move logic to engine, and adjust TypeScript usage

Author: hotlong

content/docs/references/system/plugin.mdx

@@ -27,8 +27,8 @@ const result = PluginSchema.parse(data);
 
 | Property | Type | Required | Description |
 | :--- | :--- | :--- | :--- |
-| **id** | `string` | ✅ | Unique Plugin ID (e.g. com.example.crm) |
-| **version** | `string` | ✅ | Semantic Version |
+| **id** | `string` | optional | Unique Plugin ID (e.g. com.example.crm) |
+| **version** | `string` | optional | Semantic Version |
 | **description** | `string` | optional |  |
 | **author** | `string` | optional |  |
 | **homepage** | `string` | optional |  |