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/List Devices.bru

@@ -7,9 +7,40 @@ meta {
 get {
   url: {{baseUrl}}/api/devices
   body: none
-  auth: bearer
+  auth: inherit
 }
 
-headers: {
+headers {
   Authorization: Bearer {{token}}
 }
+
+settings {
+  encodeUrl: true
+  timeout: 0
+}
+
+docs {
+  ## List Devices
+
+  Lists all devices registered to the authenticated user's account.
+
+  **Method:** GET
+
+  **Endpoint:** /api/devices
+
+  **Authentication:** Bearer token
+
+  **Response:**
+  - `devices` (array): Array of device objects
+    - `id` (string): Device UUID
+    - `name` (string): Device name
+    - `device_type` (string): Type (kobo, koreader, web)
+    - `last_sync` (string): Last sync timestamp
+    - `is_active` (boolean): Whether device is active
+    - `created_at` (string): Registration timestamp
+
+  **Status Codes:**
+  - 200: Success
+  - 401: Unauthorized
+  - 500: Internal server error
+}