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/library/Create Library.bru

@@ -22,6 +22,20 @@ body:json {
   }
 }
 
+script:post-response {
+  function onResponse(res) {
+    let data = res.getBody();
+    // If successful registration, set token environment variable
+    if (res.getStatus() === 201 || res.getStatus() === 200) {
+      if (data && data.id) {
+  
+        return bru.setEnvVar("library_id", data.id, { persist: true });
+      }
+    }
+  }
+  onResponse(res);
+}
+
 settings {
   encodeUrl: true
   timeout: 0