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/sidecar/Update System Configuration.bru

@@ -1,23 +1,67 @@
 meta {
-  name: "Update System Configuration"
+  name: Update System Configuration
   type: http
   seq: 4
 }
 
 put {
   url: {{base_url}}/api/system/config
-  body: json({
+  body: json
+  auth: inherit
+}
+
+headers {
+  Authorization: Bearer {{admin_token}}
+  Content-Type: application/json
+}
+
+body:json {
+  {
     "base_url": "https://bookhoard.example.com",
     "opds_base_url": "https://bookhoard.example.com/opds",
     "api_base_url": "https://bookhoard.example.com/api"
-  })
-  auth: {
-    type: bearer
-    bearer: {{admin_token}}
   }
 }
 
-assert {
-  response.status == 200
-  response.body.status == "success"
+script:post-response {
+  function onResponse(res) {
+    if (res.getStatus() === 200) {
+      const body = res.getBody();
+      tests('Status is success', body.status === "success");
+    }
+  }
+  onResponse(res);
+}
+
+settings {
+  encodeUrl: true
+  timeout: 0
+}
+
+docs {
+  ## Update System Configuration
+
+  Updates system-wide configuration settings for the Bookhoard instance.
+
+  **Method:** PUT
+
+  **Endpoint:** /api/system/config
+
+  **Authentication:** Bearer token (admin only)
+
+  **Request Body:**
+  - `base_url` (string): Base URL for the instance
+  - `opds_base_url` (string): OPDS endpoint base URL
+  - `api_base_url` (string): API endpoint base URL
+
+  **Response:**
+  - `status` (string): Update status
+  - `config` (object): Updated configuration
+
+  **Status Codes:**
+  - 200: Success
+  - 400: Invalid configuration
+  - 401: Unauthorized
+  - 403: Forbidden (admin only)
+  - 500: Internal server error
 }