Related to: [BS-3143](https://linear.app/affine-design/issue/BS-3143/更新-loading-和错误样式)
<!-- This is an auto-generated comment: release notes by coderabbit.ai -->
## Summary by CodeRabbit
- **New Features**
- Introduced a unified resource controller for managing image and attachment resources, providing improved loading, error, and state handling.
- Added a visual loading indicator overlay to image blocks for better feedback during image loading.
- **Improvements**
- Simplified and centralized image and attachment state management, reducing redundant properties and manual state tracking.
- Updated fallback UI for image blocks with clearer titles, descriptions, and improved layout.
- Enhanced batch image block creation and download handling for improved efficiency.
- Refined image block accessibility with improved alt text and streamlined rendering logic.
- Centralized target model selection for image insertion in AI actions.
- Reordered CSS declarations without affecting styling.
- Improved reactive state tracking for blob upload/download operations in mock server.
- **Bug Fixes**
- Improved cleanup of object URLs to prevent resource leaks.
- Adjusted toolbar logic to more accurately reflect available actions based on image state.
- **Tests**
- Updated end-to-end tests to match new UI text and behaviors for image loading and error states.
- **Chores**
- Refactored internal logic and updated comments for clarity and maintainability.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
