Import Endpoints: Improve API Playground documentation (dotCMS#31970)

### Proposed Changes
Improve the OpenAPI documentation for swagger

### Checklist
- [ ] Tests
- [ ] Translations
- [ ] Security Implications Contemplated (add notes if applicable)

### Additional Info
** any additional useful context or info **

### Screenshots
Original             |  Updated
:-------------------------:|:-------------------------:
** original screenshot **  |  ** updated screenshot **

---------

Co-authored-by: fabrizzio-dotCMS <[email protected]>
Co-authored-by: Valentino Giardino <[email protected]>
Co-authored-by: valentinogiardino <[email protected]>

Author: 3 people

dotCMS/src/main/java/com/dotcms/rest/api/v1/content/dotimport/ContentImportDocs.java

@@ -0,0 +1,31 @@
+package com.dotcms.rest.api.v1.content.dotimport;
+
+public class ContentImportDocs {
+
+    public static final String FORM_FIELD_DOC =
+            "This endpoint accepts a `multipart/form-data` request with two fields:\n\n" +
+                    "| **Field** | **Type** | **Required** | **Description** |\n" +
+                    "|-----------|----------|--------------|-----------------|\n" +
+                    "| `file`    | File     | ✅ Yes        | The CSV file to import. Must contain content rows and match the expected structure for the content type. |\n" +
+                    "| `form`    | String   | ✅ Yes        | A JSON string containing the import parameters. See structure below. |\n\n" +
+                    "**`form` field structure:**\n\n" +
+                    "| **Property**         | **Type**   | **Required** | **Default** | **Description** |\n" +
+                    "|----------------------|------------|--------------|-------------|-----------------|\n" +
+                    "| `contentType`        | String     | ✅ Yes        | –           | Content Type variable or ID to import data into. |\n" +
+                    "| `language`           | String     | ❌ No         | Default language | Language code (e.g., `en-US`) or language ID. |\n" +
+                    "| `workflowActionId`   | String     | ✅ Yes        | –           | Workflow Action UUID to apply to imported content. |\n" +
+                    "| `fields`             | String[]   | ❌ No         | –           | List of field variables or IDs used as keys for content updates. |\n" +
+                    "| `stopOnError`        | Boolean    | ❌ No         | `false`     | Whether to stop import on first validation error. |\n" +
+                    "| `commitGranularity`  | Integer    | ❌ No         | `100`       | Number of rows to commit in each transaction batch. |\n\n" +
+                    "**Example `form` value:**\n\n" +
+                    "```json\n" +
+                    "{\n" +
+                    "  \"contentType\": \"webPageContent\",\n" +
+                    "  \"language\": \"en-US\",\n" +
+                    "  \"workflowActionId\": \"b9d89c80-3d88-4311-8365-187323c96436\",\n" +
+                    "  \"fields\": [\"title\"],\n" +
+                    "  \"stopOnError\": false,\n" +
+                    "  \"commitGranularity\": 100\n" +
+                    "}\n" +
+                    "```";
+}

dotCMS/src/main/java/com/dotcms/rest/api/v1/content/dotimport/ContentImportParamsSchema.java

@@ -2,6 +2,8 @@
 
 import io.swagger.v3.oas.annotations.media.Schema;
 
+import javax.ws.rs.FormParam;
+
 /**
  * Represents the schema for content import parameters used in Swagger documentation.
  * <p>
@@ -12,6 +14,7 @@
 @Schema(description = "Schema for content import parameters.")
 public class ContentImportParamsSchema {
 
+    @FormParam("file")
     @Schema(
             description = "The CSV file to import.",
             type = "string",
@@ -20,6 +23,7 @@ public class ContentImportParamsSchema {
     )
     private String file;
 
+    @FormParam("form")
     @Schema(
             description = "JSON string representing import settings.",
             type = "string",
@@ -28,7 +32,7 @@ public class ContentImportParamsSchema {
                     "  \"contentType\": \"activity\",\n" +
                     "  \"language\": \"en-US\",\n" +
                     "  \"workflowActionId\": \"b9d89c80-3d88-4311-8365-187323c96436\",\n" +
-                    "  \"fields\": [\"e1f99107-fd0e-49d4-a099-1cc10aa284d8\"]\n" +
+                    "  \"fields\": [\"title\"]\n" +
                     "  \"stopOnError\":false \n" +
                     "  \"commitGranularity\": 100\n" +
                     "}"