refactor: update Bruno API collection for media-items system

- Remove all ebook-specific API requests (15 files deleted)
- Rename Scan Ebooks.bru to Scan Media Items.bru
- Update API paths from /api/ebooks to /api/media-items
- Update base URL and environment configuration
- Maintain all existing media-items, library, auth, and progress tests

Aligns Bruno collection with unified media-items API architecture

bruno/progress/Update Reading Progress.bru

@@ -5,7 +5,7 @@ meta {
 }
 
 put {
-  url: {{base_url}}/api/ebooks/{{ebook_id}}/progress
+  url: {{base_url}}/api/media-items/{{media_item_id}}/progress
   body: json
   auth: inherit
 }
@@ -25,12 +25,12 @@ settings {
 docs {
   ## Update Reading Progress
   
-  Updates the authenticated user's reading progress for an ebook.
+  Updates the authenticated user's reading progress for a media item.
   
   **Authentication:** Required (Bearer token)
   
   **Path Parameters:**
-  - `id` (string): Ebook UUID
+  - `id` (string): Media Item UUID
   
   **Request Body:**
   - `current_page` (number, required): Current page number