refactor: replace CSS group-hover with Radix HoverCard for message actions

Swap the fragile CSS group-hover opacity pattern for Radix HoverCard
which handles hover intent, open/close delays, and portal rendering.
Actions appear below the bubble on hover via stripped HoverCardContent
(no border, shadow, padding, or background). Removes group class.

ui/goose2/src/features/chat/ui/MessageBubble.tsx

@@ -30,6 +30,11 @@ import {
   ReasoningContent,
 } from "@/shared/ui/ai-elements/reasoning";
 import { Button } from "@/shared/ui/button";
+import {
+  HoverCard,
+  HoverCardTrigger,
+  HoverCardContent,
+} from "@/shared/ui/hover-card";
 import { ToolChainCards, type ToolChainItem } from "./ToolChainCards";
 import { ClickableImage } from "./ClickableImage";
 import { useArtifactLinkHandler } from "@/features/chat/hooks/useArtifactLinkHandler";
@@ -414,7 +419,7 @@ export const MessageBubble = memo(function MessageBubble({
   return (
     <div
       className={cn(
-        "group flex px-4 py-1",
+        "flex px-4 py-1",
         "animate-in fade-in duration-200 motion-reduce:animate-none",
         isEditing
           ? "flex-row"
@@ -494,81 +499,90 @@ export const MessageBubble = memo(function MessageBubble({
             </div>
           </div>
         ) : (
-          <>
+          <HoverCard openDelay={0} closeDelay={150}>
             {/* biome-ignore lint/a11y/useKeyWithClickEvents: delegated link handler */}
             {/* biome-ignore lint/a11y/noStaticElementInteractions: delegated link handler */}
-            <div
-              className={cn(
-                "w-full min-w-0 text-[13px] leading-relaxed",
-                isUser && "rounded-2xl bg-muted px-4 py-2.5",
-              )}
-              onClick={handleContentClick}
-            >
-              {messageAttachments.length > 0 && (
-                <div className="mb-2 flex flex-wrap gap-2">
-                  {messageAttachments.map((attachment) => (
-                    <MessageAttachmentRow
-                      key={`${attachment.type}-${attachment.path ?? attachment.name}`}
-                      attachment={attachment}
-                    />
-                  ))}
-                </div>
-              )}
-              {groupContentSections(content).map((section, sectionIdx) => {
-                if (section.type === "toolChain") {
-                  const toolItems = section.items as ToolChainItem[];
-                  return <ToolChainCards key={section.key} toolItems={toolItems} />;
-                }
-                const block = section.items[0] as MessageContent;
-                return (
-                  <div key={`${message.id}-${section.key}`}>
-                    {renderContentBlock(
-                      block,
-                      sectionIdx,
-                      {
-                        defaultImageAlt: t("message.defaultImageAlt"),
-                        redactedThinking: t("message.redactedThinking"),
-                      },
-                      isStreaming,
-                      isUser,
-                    )}
+            <HoverCardTrigger asChild>
+              <div
+                className={cn(
+                  "w-full min-w-0 text-[13px] leading-relaxed",
+                  isUser && "rounded-2xl bg-muted px-4 py-2.5",
+                )}
+                onClick={handleContentClick}
+              >
+                {messageAttachments.length > 0 && (
+                  <div className="mb-2 flex flex-wrap gap-2">
+                    {messageAttachments.map((attachment) => (
+                      <MessageAttachmentRow
+                        key={`${attachment.type}-${attachment.path ?? attachment.name}`}
+                        attachment={attachment}
+                      />
+                    ))}
                   </div>
-                );
-              })}
-              {pathNotice && (
-                <p className="mt-2 text-xs text-destructive" role="status">
-                  {pathNotice}
-                </p>
-              )}
-            </div>
-
-            {/* Hover actions + timestamp */}
-            <MessageActions className="opacity-0 transition-opacity duration-150 group-hover:opacity-100">
-              {textContent && <CopyAction text={textContent} />}
-              {onRetryMessage && (
-                <MessageAction
-                  tooltip={t("common:actions.retry")}
-                  onClick={() => onRetryMessage(message.id)}
-                >
-                  <RotateCcw className="size-3.5" />
-                </MessageAction>
-              )}
-              {isUser && onEditMessage && !isEditing && (
-                <MessageAction
-                  tooltip={t("common:actions.edit")}
-                  onClick={() => onEditMessage(message.id)}
-                >
-                  <Pencil className="size-3.5" />
-                </MessageAction>
-              )}
-              <span className="px-1 text-[10px] text-muted-foreground">
-                {formatDate(created, {
-                  hour: "2-digit",
-                  minute: "2-digit",
+                )}
+                {groupContentSections(content).map((section, sectionIdx) => {
+                  if (section.type === "toolChain") {
+                    const toolItems = section.items as ToolChainItem[];
+                    return <ToolChainCards key={section.key} toolItems={toolItems} />;
+                  }
+                  const block = section.items[0] as MessageContent;
+                  return (
+                    <div key={`${message.id}-${section.key}`}>
+                      {renderContentBlock(
+                        block,
+                        sectionIdx,
+                        {
+                          defaultImageAlt: t("message.defaultImageAlt"),
+                          redactedThinking: t("message.redactedThinking"),
+                        },
+                        isStreaming,
+                        isUser,
+                      )}
+                    </div>
+                  );
                 })}
-              </span>
-            </MessageActions>
-          </>
+                {pathNotice && (
+                  <p className="mt-2 text-xs text-destructive" role="status">
+                    {pathNotice}
+                  </p>
+                )}
+              </div>
+            </HoverCardTrigger>
+
+            {/* Hover actions + timestamp — rendered in portal, stripped styling */}
+            <HoverCardContent
+              side="bottom"
+              align={isUser ? "end" : "start"}
+              sideOffset={0}
+              className="w-auto border-none bg-transparent p-0 shadow-none"
+            >
+              <MessageActions>
+                {textContent && <CopyAction text={textContent} />}
+                {onRetryMessage && (
+                  <MessageAction
+                    tooltip={t("common:actions.retry")}
+                    onClick={() => onRetryMessage(message.id)}
+                  >
+                    <RotateCcw className="size-3.5" />
+                  </MessageAction>
+                )}
+                {isUser && onEditMessage && (
+                  <MessageAction
+                    tooltip={t("common:actions.edit")}
+                    onClick={() => onEditMessage(message.id)}
+                  >
+                    <Pencil className="size-3.5" />
+                  </MessageAction>
+                )}
+                <span className="px-1 text-[10px] text-muted-foreground">
+                  {formatDate(created, {
+                    hour: "2-digit",
+                    minute: "2-digit",
+                  })}
+                </span>
+              </MessageActions>
+            </HoverCardContent>
+          </HoverCard>
         )}
       </div>
     </div>