refactor(chat): improve AssistantMessage component with fixed comment trigger slot and enhanced visibility handling

surfsense_web/components/assistant-ui/assistant-message.tsx

@@ -548,9 +548,11 @@ const AssistantMessageInner: FC = () => {
 				</div>
 			)}
 
-			<div className="aui-assistant-message-footer mt-3 mb-5 ml-2 flex items-center gap-2">
+			<div className="aui-assistant-message-footer mt-3 mb-5 ml-2 h-6">
+				<div className="h-full opacity-100 transition-opacity">
 					<AssistantActionBar />
 				</div>
+			</div>
 		</CitationMetadataProvider>
 	);
 };
@@ -642,17 +644,24 @@ export const AssistantMessage: FC = () => {
 			className="aui-assistant-message-root group fade-in slide-in-from-bottom-1 relative mx-auto w-full max-w-(--thread-max-width) animate-in py-3 duration-150"
 			data-role="assistant"
 		>
-			{/* Comment trigger — right-aligned, just below user query on all screen sizes */}
-			{showCommentTrigger && (
-				<div className="mr-2 mb-1 flex justify-end">
+			{/* Fixed trigger slot prevents any vertical reflow when visibility changes */}
+			<div className="mr-2 mb-1 flex h-7 justify-end">
 				<button
 					ref={isDesktop ? commentTriggerRef : undefined}
 					type="button"
 					onClick={
-							isDesktop ? () => setIsInlineOpen((prev) => !prev) : () => setIsSheetOpen(true)
+						showCommentTrigger
+							? isDesktop
+								? () => setIsInlineOpen((prev) => !prev)
+								: () => setIsSheetOpen(true)
+							: undefined
 					}
+					aria-hidden={!showCommentTrigger}
+					tabIndex={showCommentTrigger ? 0 : -1}
 					className={cn(
 						"flex items-center gap-1.5 rounded-full px-3 py-1 text-sm transition-colors",
+						"opacity-0 pointer-events-none",
+						showCommentTrigger && "opacity-100 pointer-events-auto",
 						isDesktop && isInlineOpen
 							? "bg-primary/10 text-primary"
 							: hasComments
@@ -670,7 +679,6 @@ export const AssistantMessage: FC = () => {
 					)}
 				</button>
 			</div>
-			)}
 
 			{/* Desktop floating comment panel — overlays on top of chat content */}
 			{showCommentTrigger && isDesktop && isInlineOpen && dbMessageId && (