docs(rest): rule schema API

Signed-off-by: Jiyong Huang <huangjy@emqx.io>

Author: ngjaying

docs/en_US/api/restapi/rules.md

@@ -74,6 +74,32 @@ Response Sample:
 }
 ```
 
+## get schema of a rule
+
+This API allows you to retrieve the output schema of a specific rule. The schema describes the fields and their
+properties (like hasIndex and index) that are produced by the rule's SELECT statement.
+
+```shell
+GET http://localhost:9081/rules/{id}
+```
+
+Path parameter `id` is the id of the rule.
+
+Example response when using slice mode:
+
+```json
+{
+  "id": {
+    "hasIndex": true,
+    "index": 0
+  },
+  "name": {
+    "hasIndex": true,
+    "index": 1
+  }
+}
+```
+
 ## update a rule
 
 The API accepts a JSON content and update a rule.

docs/en_US/api/restapi/streams.md

@@ -86,7 +86,7 @@ Response Sample:
 }
 ```
 
-## Get stream schema
+## get stream schema
 
 The API is used to get the stream schema. The schema is inferred from the physical and logical schema definitions.
 
@@ -127,6 +127,9 @@ The format is like Json schema:
 }
 ```
 
+For a shared stream, the schema adjusts dynamically during runtime according to the active processing rules. To reduce
+computational overhead, the system maintains only the minimal schema needed to support those rules.
+
 ## update a stream
 
 The API is used for update the stream definition.

docs/zh_CN/api/restapi/rules.md

@@ -74,6 +74,36 @@ GET http://localhost:9081/rules/{id}
 }
 ```
 
+### 中文技术文档翻译（符合API文档规范）
+
+---
+
+## 获取规则输出模式
+
+本接口用于获取指定规则生成的输出模式。该模式描述了规则通过SELECT语句生成的字段及其属性（如`hasIndex`和`index`）。
+
+```shell
+GET http://localhost:9081/rules/{id}
+```
+
+**路径参数**  
+`id` : 规则唯一标识符
+
+**示例响应**：
+
+```json
+{
+  "id": {
+    "hasIndex": true,
+    "index": 0
+  },
+  "name": {
+    "hasIndex": true,
+    "index": 1
+  }
+}
+```
+
 ## 更新规则
 
 该 API 接受 JSON 内容并更新规则。

docs/zh_CN/api/restapi/streams.md

@@ -108,6 +108,8 @@ GET http://localhost:9081/streams/{id}/schema
 }
 ```
 
+对于共享数据流，其模式会根据运行时生效的处理规则进行动态调整。为降低计算开销，系统仅维护支持当前规则所需的最小化模式。
+
 ## 更新流
 
 该 API 用于更新流定义。