docs: refine cover image serving API documentation with static URL patterns

Update Bruno collection test documentation to reflect the new unified static-style
URL strategy for cover images and media downloads.

Changes:
- Update cover image endpoint from /api/covers/{id} to /uploads/library-{id}/{path}
- Update download endpoint from /api/media-items/{id}/download to /uploads/library-{id}/{path}
- Document JWT authentication for static endpoints (same as API endpoints)
- Add clarification that resolved URLs come from API responses
- Update status codes to reflect new endpoint behavior
- Rename 'Download Media Item.yml' to 'EPUB Download.yml' for clarity

This documentation aligns with the unified URL strategy where all file access
goes through a consistent /uploads/library-{id}/ pattern with JWT-based
authentication, eliminating separate API endpoints for file serving.

cover_image_serving_plan.md

@@ -524,17 +524,18 @@ info:
   seq: 1
 http:
   method: GET
-  url: '{{base_url}}/api/covers/{{media_item_id}}'
+  url: '{{base_url}}/uploads/library-{{library_id}}/path/to/cover.jpg'
   auth: none
 
 docs: |-
   ## Get Cover Image
   
-  Retrieve the cover image for a media item. Requires authentication.
+  Retrieve the cover image for a media item via authenticated static-style URL.
+  Uses JWT authentication (same as API endpoints).
   
   **Method:** GET
   
-  **Endpoint:** /api/covers/{id}
+  **Endpoint:** /uploads/library-{id}/{path}
   
   **Authentication:** Bearer token required
   
@@ -542,16 +543,19 @@ docs: |-
   
   **Status Codes:**
   - 200: Success - returns image
-  - 400: Invalid media item ID
-  - 401: Unauthorized
-  - 404: Media item not found or cover doesn't exist
+  - 401: Unauthorized (missing/invalid JWT)
+  - 404: File not found
+  
+  **Note:** The actual path would come from the API response which provides
+  the resolved URL. This test is a template showing the URL format.
 
-Note: Uses `media_item_id` from environment variables.
+vars:
+  library_id: ""
 ```
 
-#### File: `bruno/media-items/Download Media Item.yml` (Update existing)
+#### File: `bruno/media-items/EPUB Download.yml` (Update existing)
 
-Update the existing file to document that it now handles relative paths:
+Update the existing file to note that downloads now work through the same `/uploads/library-{id}/` endpoint:
 
 ```yaml
 info:
@@ -560,17 +564,18 @@ info:
   seq: 1
 http:
   method: GET
-  url: '{{base_url}}/api/media-items/{{media_item_id}}/download'
+  url: '{{base_url}}/uploads/library-{{library_id}}/path/to/book.epub'
   auth: none
 
 docs: |-
   ## Download Media Item
   
-  Download a media item file (EPUB, PDF, CBZ, etc.) from Bookhoard server.
+  Download a media item file (EPUB, PDF, CBZ, etc.) via authenticated static-style URL.
+  Uses JWT authentication (same as API endpoints).
   
   **Method:** GET
   
-  **Endpoint:** /api/media-items/{id}/download
+  **Endpoint:** /uploads/library-{id}/{path}
   
   **Authentication:** Bearer token required
   
@@ -584,11 +589,14 @@ docs: |-
   
   **Status Codes:**
   - 200: Success - returns file
-  - 400: Invalid media item ID
-  - 401: Unauthorized
-  - 404: Media item not found or file doesn't exist on disk
+  - 401: Unauthorized (missing/invalid JWT)
+  - 404: File not found
+  
+  **Note:** The actual path would come from the API response which provides
+  the resolved URL. This test shows the URL format.
 
-Note: Uses `media_item_id` from environment variables.
+vars:
+  library_id: ""
 ```
 
 ---