refactor(bruno): migrate API tests to Bruno DSL format

- Convert all existing .bru files from JSON to Bruno DSL format
- Remove obsolete files (conflicts/api.bru, kobo/Kobo Initialization.bru)
- Update auth configuration to use 'inherit' instead of explicit bearer tokens
- Add comprehensive documentation to all test files
- Improve test scripts with proper assertions and error handling

bruno/devices/Reject Device Registration.bru

@@ -7,36 +7,32 @@ meta {
 post {
   url: {{base_url}}/api/devices/reject/{{registration_id}}
   body: none
-  auth: bearer
-}
-
-headers: {
-  Authorization: Bearer {{token}}
+  auth: inherit
 }
 
 docs {
   ## Reject Device Registration
-  
+
   Rejects a pending device registration request.
-  
+
   **Method:** POST
-  
+
   **Endpoint:** /api/devices/reject/:registration_id
-  
+
   **Authentication:** Bearer token
-  
+
   **Path Parameters:**
    - `registration_id` (string): Registration request UUID
-  
+
   **Response:**
    - Success message confirming rejection
-  
+
   **Status Codes:**
    - 200: Success
    - 401: Unauthorized
    - 404: Registration not found
    - 400: Invalid registration status
-  
+
   **Example Response:**
    ```json
    {