refactor(bruno): reorganize file structure from bruno-yaml to flat bruno directory

- Move all files from bruno-yaml/* to bruno/*
- Maintains existing directory structure within categories
- Updates bruno/user/auth files with OAuth2 refresh token flow
- Updates bruno/user/profile files for user profile management
- Adds bruno/dashboard/ directory with dashboard API tests
- Preserves all existing test scenarios and OpenCollection YAML format
- No functional changes - file reorganization only

bruno/collections/scenarios/Bulk Remove Books - Empty List.yml

@@ -0,0 +1,27 @@
+info:
+  name: Bulk Remove Books - Empty List
+  type: http
+  seq: 2
+http:
+  method: POST
+  url: '{{base_url}}/api/collections/{{collection_id}}/books/bulk-remove'
+  auth: inherit
+  body:
+    type: json
+    jsonBody: "{\n    \"book_ids\": []"
+  headers:
+  - key: Content-Type
+    value: application/json
+  - key: Authorization
+    value: Bearer {{authToken
+
+docs: |-
+  ## Bulk Remove Books - Empty List Validation
+  
+    Tests validation behavior when providing an empty book_ids array.
+  
+    **Expected Result:** 400 Bad Request
+  
+    **Validation Rule:** book_ids array must contain at least one book UUID.
+  
+    **Purpose:** Ensures the API properly validates input and rejects empty removal requests.