fix HistoryEntry children prop conflict and overlay CopyButton in ContentViewer

Rename HistoryEntry's children prop to childEntries to avoid React's
reserved prop name. Replace ContentViewer's onCopy callback with a
copyable flag and overlay CopyButton in the top-right corner.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

clients/web/src/components/atoms/ContentViewer/ContentViewer.stories.tsx

@@ -1,5 +1,4 @@
 import type { Meta, StoryObj } from "@storybook/react-vite";
-import { fn } from "storybook/test";
 import { ContentViewer } from "./ContentViewer";
 
 const meta: Meta<typeof ContentViewer> = {
@@ -74,6 +73,15 @@ export const WithCopyButton: Story = {
   args: {
     type: "text",
     content: "Hello, world!\nThis text can be copied.",
-    onCopy: fn(),
+    copyable: true,
+  },
+};
+
+export const JsonWithCopy: Story = {
+  args: {
+    type: "json",
+    content:
+      '{"name":"my-app","version":"1.0.0","description":"Sample configuration file"}',
+    copyable: true,
   },
 };

clients/web/src/components/atoms/ContentViewer/ContentViewer.tsx

@@ -1,10 +1,11 @@
-import { Button, Code, Image, Stack } from "@mantine/core";
+import { Code, Flex, Image, Stack } from "@mantine/core";
+import { CopyButton } from "../CopyButton/CopyButton";
 
 export interface ContentViewerProps {
   type: "text" | "json" | "image" | "audio";
   content: string;
   mimeType?: string;
-  onCopy?: () => void;
+  copyable?: boolean;
 }
 
 function formatJson(content: string): string {
@@ -15,16 +16,33 @@ function formatJson(content: string): string {
   }
 }
 
+const ContentWrapper = Flex.withProps({
+  pos: "relative",
+  direction: "column",
+});
+
 export function ContentViewer({
   type,
   content,
   mimeType,
-  onCopy,
+  copyable = false,
 }: ContentViewerProps) {
+  const showCopy = copyable && (type === "text" || type === "json");
+
   return (
     <Stack gap="xs">
-      {type === "json" && <Code block>{formatJson(content)}</Code>}
+      {(type === "json" || type === "text") && (
-      {type === "text" && <Code block>{content}</Code>}
+        <ContentWrapper>
+          <Code block p={36}>
+            {type === "json" ? formatJson(content) : content}
+          </Code>
+          {showCopy && (
+            <Flex pos="absolute" top={4} right={4}>
+              <CopyButton value={content} />
+            </Flex>
+          )}
+        </ContentWrapper>
+      )}
       {type === "image" && (
         <Image
           src={`data:${mimeType || "image/png"};base64,${content}`}
@@ -38,11 +56,6 @@ export function ContentViewer({
           <source src={`data:${mimeType || "audio/wav"};base64,${content}`} />
         </audio>
       )}
-      {onCopy && (
-        <Button variant="light" size="xs" onClick={onCopy}>
-          Copy
-        </Button>
-      )}
     </Stack>
   );
 }

clients/web/src/components/molecules/HistoryEntry/HistoryEntry.stories.tsx

@@ -75,7 +75,7 @@ export const WithChildren: Story = {
     response: {
       result: "completed",
     },
-    children: [
+    childEntries: [
       {
         timestamp: "+120ms",
         method: "sampling/createMessage",

clients/web/src/components/molecules/HistoryEntry/HistoryEntry.tsx

@@ -25,7 +25,7 @@ export interface HistoryEntryProps {
   durationMs: number;
   parameters?: Record<string, unknown>;
   response?: Record<string, unknown>;
-  children?: HistoryChildEntry[];
+  childEntries?: HistoryChildEntry[];
   isPinned: boolean;
   pinLabel?: string;
   isExpanded: boolean;
@@ -42,7 +42,7 @@ export function HistoryEntry({
   durationMs,
   parameters,
   response,
-  children,
+  childEntries,
   isPinned,
   pinLabel,
   isExpanded,
@@ -102,9 +102,9 @@ export function HistoryEntry({
                 <Code block>{JSON.stringify(response, null, 2)}</Code>
               </Stack>
             )}
-            {children && children.length > 0 && (
+            {childEntries && childEntries.length > 0 && (
               <Stack gap="xs">
-                {children.map((child, index) => (
+                {childEntries.map((child, index) => (
                   <Group key={index} pl="lg" gap="sm">
                     <Text size="sm" c="dimmed" ff="monospace">
                       +--{" "}