feat(messages): code blocks get a Wrap toggle next to Copy (#131)

Verified upstream first: the Copy chip (with a 'Copied' state) already exists
on every code block. Added the missing half: a Wrap chip that switches long
lines to pre-wrap (default stays no-wrap + horizontal scroll); the choice is
remembered for the session, not persisted. Markdown/HTML output, layout widths
and the syntax theme are untouched. Verified headless: scrollWidth 1016 →
612 px with wrapping on, 'Copied' state on copy.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PPmy3tPq869XDW4njjVaKA

src/app/plugins/react-custom-html-parser.tsx

@@ -333,13 +333,10 @@ const extractTextFromChildren = (nodes: ChildNode[]): string => {
   return text;
 };
 
-export function CodeBlock({
+export // Session memory for the code-block Wrap toggle (#131).
-  children,
+const codeWrapPreference = { value: false };
-  opts,
+
-}: {
+function CodeBlock({ children, opts }: { children: ChildNode[]; opts: HTMLReactParserOptions }) {
-  children: ChildNode[];
-  opts: HTMLReactParserOptions;
-}) {
   const code = children[0];
   const attribs = code instanceof Element && code.name === 'code' ? code.attribs : undefined;
   const languageClass = attribs?.class;
@@ -357,6 +354,13 @@ export function CodeBlock({
 
   const [expanded, setExpand] = useState(false);
   const [copied, setCopied] = useTimeoutToggle();
+  // [Gitea #131] Line-wrap toggle for long lines; the choice is remembered for
+  // the session (module-level), not persisted.
+  const [wrap, setWrap] = useState(codeWrapPreference.value);
+  const toggleWrap = () => {
+    codeWrapPreference.value = !wrap;
+    setWrap(!wrap);
+  };
 
   const handleCopy = () => {
     copyToClipboard(extractTextFromChildren(children));
@@ -376,6 +380,16 @@ export function CodeBlock({
           </Text>
         </Box>
         <Box shrink="No" gap="200">
+          <Chip
+            variant={wrap ? 'Primary' : 'Surface'}
+            fill="None"
+            radii="Pill"
+            onClick={toggleWrap}
+            aria-pressed={wrap}
+            title={wrap ? 'Scroll long lines instead of wrapping' : 'Wrap long lines'}
+          >
+            <Text size="B300">Wrap</Text>
+          </Chip>
           <Chip
             variant={copied ? 'Success' : 'Surface'}
             fill="None"
@@ -410,7 +424,11 @@ export function CodeBlock({
         visibility="Hover"
         hideTrack
       >
-        <div id="code-block-content" className={css.CodeBlockInternal}>
+        <div
+          id="code-block-content"
+          className={css.CodeBlockInternal}
+          style={wrap ? { whiteSpace: 'pre-wrap', overflowWrap: 'anywhere' } : undefined}
+        >
           {domToReact(children as unknown as DOMNode[], opts)}
         </div>
       </Scroll>