docs: improve api documentation for advanced chat and workflow (#9882)

web/app/components/develop/template/template_workflow.en.mdx

@@ -44,6 +44,7 @@ Workflow applications offers non-session support and is ideal for translation, a
         Allows the entry of various variable values defined by the App.
         The `inputs` parameter contains multiple key/value pairs, with each key corresponding to a specific variable and each value being the specific value for that variable.
         The workflow application requires at least one key/value pair to be inputted.
+        If the variable is of File type, specify an object that has the keys described in `files` below.
       - `response_mode` (string) Required
         The mode of response return, supporting:
         - `streaming` Streaming mode (recommended), implements a typewriter-like output through SSE ([Server-Sent Events](https://developer.mozilla.org/en-US/docs/Web/API/Server-sent_events/Using_server-sent_events)).
@@ -328,6 +329,81 @@ Workflow applications offers non-session support and is ideal for translation, a
 
 ---
 
+<Heading
+  url='/files/upload'
+  method='POST'
+  title='File Upload'
+  name='#file-upload'
+/>
+<Row>
+  <Col>
+  Upload a file for use when sending messages, enabling multimodal understanding of images and text.
+  Supports any formats that are supported by your workflow.
+  Uploaded files are for use by the current end-user only.
+
+  ### Request Body
+  This interface requires a `multipart/form-data` request.
+  - `file` (File) Required
+    The file to be uploaded.
+  - `user` (string) Required
+    User identifier, defined by the developer's rules, must be unique within the application.
+
+  ### Response
+  After a successful upload, the server will return the file's ID and related information.
+  - `id` (uuid) ID
+  - `name` (string) File name
+  - `size` (int) File size (bytes)
+  - `extension` (string) File extension
+  - `mime_type` (string) File mime-type
+  - `created_by` (uuid) End-user ID
+  - `created_at` (timestamp) Creation timestamp, e.g., 1705395332
+
+  ### Errors
+  - 400, `no_file_uploaded`, a file must be provided
+  - 400, `too_many_files`, currently only one file is accepted
+  - 400, `unsupported_preview`, the file does not support preview
+  - 400, `unsupported_estimate`, the file does not support estimation
+  - 413, `file_too_large`, the file is too large
+  - 415, `unsupported_file_type`, unsupported extension, currently only document files are accepted
+  - 503, `s3_connection_failed`, unable to connect to S3 service
+  - 503, `s3_permission_denied`, no permission to upload files to S3
+  - 503, `s3_file_too_large`, file exceeds S3 size limit
+  - 500, internal server error
+
+
+  </Col>
+  <Col sticky>
+  ### Request Example
+  <CodeGroup title="Request" tag="POST" label="/files/upload" targetCode={`curl -X POST '${props.appDetail.api_base_url}/files/upload' \\\n--header 'Authorization: Bearer {api_key}' \\\n--form 'file=@localfile;type=image/[png|jpeg|jpg|webp|gif] \\\n--form 'user=abc-123'`}>
+
+    ```bash {{ title: 'cURL' }}
+    curl -X POST '${props.appDetail.api_base_url}/files/upload' \
+    --header 'Authorization: Bearer {api_key}' \
+    --form 'file=@"/path/to/file"'
+    ```
+
+    </CodeGroup>
+
+
+  ### Response Example
+  <CodeGroup title="Response">
+    ```json {{ title: 'Response' }}
+    {
+      "id": "72fa9618-8f89-4a37-9b33-7e1178a24a67",
+      "name": "example.png",
+      "size": 1024,
+      "extension": "png",
+      "mime_type": "image/png",
+      "created_by": "6ad1ab0a-73ff-4ac1-b9e4-cdb312f71f13",
+      "created_at": 1577836800,
+    }
+  ```
+  </CodeGroup>
+  </Col>
+</Row>
+
+---
+
 <Heading
   url='/parameters'
   method='GET'