🎞️ refactor: Image Rendering with Preview Caching and Layout Reservation (#12114)

* refactor: Update Image Component to Remove Lazy Loading and Enhance Rendering

- Removed the react-lazy-load-image-component dependency from the Image component, simplifying the image loading process.
- Updated the Image component to use a standard <img> tag with async decoding for improved performance and user experience.
- Adjusted related tests to reflect changes in image rendering behavior and ensure proper functionality without lazy loading.

* refactor: Enhance Image Handling and Caching Across Components

- Introduced a new previewCache utility for managing local blob preview URLs, improving image loading efficiency.
- Updated the Image component and related parts (FileRow, Files, Part, ImageAttachment, LogContent) to utilize cached previews, enhancing rendering performance and user experience.
- Added width and height properties to the Image component for better layout management and consistency across different usages.
- Improved file handling logic in useFileHandling to cache previews during file uploads, ensuring quick access to image data.
- Enhanced overall code clarity and maintainability by streamlining image rendering logic and reducing redundancy.

* refactor: Enhance OpenAIImageGen Component with Image Dimensions

- Added width and height properties to the OpenAIImageGen component for improved image rendering and layout management.
- Updated the Image component usage within OpenAIImageGen to utilize the new dimensions, enhancing visual consistency and performance.
- Improved code clarity by destructuring additional properties from the attachment object, streamlining the component's logic.

* refactor: Implement Image Size Caching in DialogImage Component

- Introduced an imageSizeCache to store and retrieve image sizes, enhancing performance by reducing redundant fetch requests.
- Updated the getImageSize function to first check the cache before making network requests, improving efficiency in image handling.
- Added decoding attribute to the image element for optimized rendering behavior.

* refactor: Enhance UserAvatar Component with Avatar Caching and Error Handling

- Introduced avatar caching logic to optimize avatar resolution based on user ID and avatar source, improving performance and reducing redundant image loads.
- Implemented error handling for failed image loads, allowing for fallback to a default avatar when necessary.
- Updated UserAvatar props to streamline the interface by removing the user object and directly accepting avatar-related properties.
- Enhanced overall code clarity and maintainability by refactoring the component structure and logic.

* fix: Layout Shift in Message and Placeholder Components for Consistent Height Management

- Adjusted the height of the PlaceholderRow and related message components to ensure consistent rendering with a minimum height of 31px.
- Updated the MessageParts and ContentRender components to utilize a minimum height for better layout stability.
- Enhanced overall code clarity by standardizing the structure of message-related components.

* tests: Update FileRow Component to Prefer Cached Previews for Image Rendering

- Modified the image URL selection logic in the FileRow component to prioritize cached previews over file paths when uploads are complete, enhancing rendering performance and user experience.
- Updated related tests to reflect changes in image URL handling, ensuring accurate assertions for both preview and file path scenarios.
- Introduced a fallback mechanism to use file paths when no preview exists, improving robustness in file handling.

* fix: Image cache lifecycle and dialog decoding

- Add deletePreview/clearPreviewCache to previewCache.ts for blob URL cleanup
- Wire deletePreview into useFileDeletion to revoke blobs on file delete
- Move dimensionCache.set into useMemo to avoid side effects during render
- Extract IMAGE_MAX_W_PX constant (512) to document coupling with max-w-lg
- Export _resetImageCaches for test isolation
- Change DialogImage decoding from "sync" to "async" to avoid blocking main thread

* fix: Avatar cache invalidation and cleanup

- Include avatarSrc in cache invalidation to prevent stale avatars
- Remove unused username parameter from resolveAvatar
- Skip caching when userId is empty to prevent cache key collisions

* test: Fix test isolation and type safety

- Reset module-level dimensionCache/paintedUrls in beforeEach via _resetImageCaches
- Replace any[] with typed mock signature in cn mock for both test files

* chore: Code quality improvements from review

- Use barrel imports for previewCache in Files.tsx and Part.tsx
- Single Map.get with truthy check instead of has+get in useEventHandlers
- Add JSDoc comments explaining EmptyText margin removal and PlaceholderRow height
- Fix FileRow toast showing "Deleting file" when file isn't actually deleted (progress < 1)

* fix: Address remaining review findings (R1-R3)

- Add deletePreview calls to deleteFiles batch path to prevent blob URL leaks
- Change useFileDeletion import from deep path to barrel (~/utils)
- Change useMemo to useEffect for dimensionCache.set (side effect, not derived value)

* fix: Address audit comments 2, 5, and 7

- Fix files preservation to distinguish null (missing) from [] (empty) in finalHandler
- Add auto-revoke on overwrite in cachePreview to prevent leaked blobs
- Add removePreviewEntry for key transfer without revoke
- Clean up stale temp_file_id cache entry after promotion to permanent file_id

client/src/components/Chat/Messages/ui/MessageRender.tsx

@@ -152,7 +152,7 @@ const MessageRender = memo(function MessageRender({
         )}
 
         <div className="flex flex-col gap-1">
-          <div className="flex max-w-full flex-grow flex-col gap-0">
+          <div className="flex min-h-[20px] max-w-full flex-grow flex-col gap-0">
             <MessageContext.Provider value={messageContextValue}>
               <MessageContent
                 ask={ask}