feat(ui): enable drag-and-drop attachments and image previews in chat (#390)

* feat(BottomTerminalDock): add close button next to the fullscreen toggle in the dock

* style: replace hardcoded gradient with theme value in shine text variant

* fix(header): adapt instance button for desktop only

* refactor(chat): polish sticky turn UX and message action rows for better readability

Switch to stable sticky-only turn behavior and redesign user/assistant action controls (placement, hover rules, ordering, spacing, selection-safe clamp) to reduce visual noise and improve interaction flow.

* feat(chat/message): refactor buttons in messages footer

* feat: enhance image preview functionality in chat messages

- Added a new ImagePreviewDialog component to handle image previews with navigation support.
- Updated ToolOutputDialog to utilize the new ImagePreviewDialog for displaying images.
- Modified the ToolPopupContent type to include a gallery of images and an index for the current image.
- Removed the old inline image display logic from ToolOutputDialog.
- Improved file handling in the file store, including better MIME type guessing and handling of server paths.
- Introduced a new API endpoint for handling large session message payloads, allowing for better management of multi-file attachments.
- Updated the VSCode bridge to support session message requests with appropriate headers and body handling.

* feat(proxy): implement SSE forwarding and enhance generic API request handling

* feat(chat): support submitting only queued messages

* feat: add image preview transition state

* fix: default VSCode view to draft and fixed sessions list regression

packages/ui/src/components/chat/ChatMessage.tsx

@@ -888,7 +888,7 @@ const ChatMessage: React.FC<ChatMessageProps> = ({
                 className={cn(
                     'group w-full',
                     shouldShowHeader ? 'pt-6' : 'pt-0',
-                    isUser ? 'pb-4' : isFollowedByAssistant ? 'pb-0' : 'pb-8'
+                    isUser ? 'pb-0' : isFollowedByAssistant ? 'pb-0' : 'pb-8'
                 )}
                 data-message-id={message.info.id}
                 ref={messageContainerRef}