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/environments/Bookhoard.yml

@@ -0,0 +1,34 @@
+name: Bookhoard
+variables:
+  - name: base_url
+    value: http://localhost:8765
+  - name: media_item_id
+    value: 02a535a4-19f8-43fa-b81b-89a226d19dd9
+  - name: fake_book_id
+    value: 123e4567-e89b-12d3-a456-426614174000
+  - name: user_id
+    value: c51118f0-31fc-4c32-827d-517d6599bf21
+  - name: highlight_id
+    value: 660f9501-f29b-51d4-b716-446655440001
+  - name: note_id
+    value: 7710a602-g29b-61d4-c716-446655440002
+  - name: library_id
+    value: cc23c3a7-f8fb-451a-a78d-2a16df1b725a
+  - name: job_id
+    value: 550e8400-e29b-41d4-a716-446655440000
+  - name: rating
+    value: "5"
+  - name: is_visible
+    value: "true"
+  - name: library_folder
+    value: /app/uploads
+  - name: opds_base_url
+    value: ""
+  - secret: true
+    name: token
+  - secret: true
+    name: refresh_token
+  - secret: true
+    name: kobo_device_token
+  - secret: true
+    name: other_device_id