docs: drop stale interactive API Explorer references

The explorer page was never routed and its client module is removed
in the preceding refactor; the endpoint docs render examples
statically.

docs/developer/development.md

@@ -21,7 +21,7 @@ Welcome to the Bookhoard developer documentation. This section contains API refe
 
 ### Split Endpoint Documentation
 
-Browse individual endpoint documentation with interactive API Explorer:
+Browse individual endpoint documentation:
 
 - **[API Documentation](api/api-reference.md)** - Split endpoint docs
   - [Authentication](api/authentication/login.md) - Register, login, tokens

docs/index.md

@@ -29,7 +29,7 @@ Complete guide to Bookhoard documentation. Find what you need quickly.
 
 - **API Documentation**
   - [Complete API Reference](developer/api-reference.md) - Monolithic REST API reference (1,300+ lines)
-  - [Split Endpoint Docs](developer/api/api-reference.md) - Individual endpoints with interactive API Explorer
+  - [Split Endpoint Docs](developer/api/api-reference.md) - Individual endpoint docs
   - [Collections API](developer/api/collections/list_collections.md) - Collections management API
   - [Admin API](developer/api/admin/) - User management (admin operations)
   - [Media Items API](developer/api/media-items/) - Media item operations including bulk operations and downloads