docs: 重构 API 参考文档，拆分为独立文件并统一 CLI 风格格式

docs/api_reference/openai/Retrieve model.md

@@ -0,0 +1,69 @@
+## Retrieve model
+
+**get** `/models/{model}`
+
+Retrieves a model instance, providing basic information about the model such as the owner and permissioning.
+
+### Path Parameters
+
+- `model: string`
+
+### Returns
+
+- `Model object { id, created, object, owned_by }`
+
+  Describes an OpenAI model offering that can be used with the API.
+
+  - `id: string`
+
+    The model identifier, which can be referenced in the API endpoints.
+
+  - `created: number`
+
+    The Unix timestamp (in seconds) when the model was created.
+
+  - `object: "model"`
+
+    The object type, which is always "model".
+
+    - `"model"`
+
+  - `owned_by: string`
+
+    The organization that owns the model.
+
+### Example
+
+```http
+curl https://api.openai.com/v1/models/$MODEL \
+    -H "Authorization: Bearer $OPENAI_API_KEY"
+```
+
+#### Response
+
+```json
+{
+  "id": "id",
+  "created": 0,
+  "object": "model",
+  "owned_by": "owned_by"
+}
+```
+
+### Example
+
+```http
+curl https://api.openai.com/v1/models/VAR_chat_model_id \
+  -H "Authorization: Bearer $OPENAI_API_KEY"
+```
+
+#### Response
+
+```json
+{
+  "id": "VAR_chat_model_id",
+  "object": "model",
+  "created": 1686935002,
+  "owned_by": "openai"
+}
+```