feat(review): add focused thread highlight and headerSlot to ThreadList

- FOCUSED_BG and FOCUSED_BORDER tokens in feedbackStyles
- headerSlot prop for draft pin comment input above thread list
- focusedThreadId prop highlights active thread row with accent border
- ThreadListItem gains focused prop with left border + subtle background

frontend/src/components/feedback/ThreadList.tsx

@@ -29,6 +29,10 @@ interface ThreadListProps {
   newCommentText: string;
   onNewCommentChange: (text: string) => void;
   onCreateThread: () => void;
+  /** Optional slot rendered above the thread list (e.g., draft pin input) */
+  headerSlot?: React.ReactNode;
+  /** Currently focused thread ID for highlighting */
+  focusedThreadId?: string | null;
 }
 
 export default function ThreadList({
@@ -45,6 +49,8 @@ export default function ThreadList({
   newCommentText,
   onNewCommentChange,
   onCreateThread,
+  headerSlot,
+  focusedThreadId,
 }: ThreadListProps) {
   const [showOrphans, setShowOrphans] = React.useState(false);
 
@@ -154,6 +160,9 @@ export default function ThreadList({
         </div>
       )}
 
+      {/* Draft pin comment input (injected from FeedbackPanel) */}
+      {headerSlot}
+
       {/* Thread list */}
       <div style={{ flex: 1, overflowY: 'auto', scrollbarWidth: 'thin', scrollbarColor: '#2a2a2e transparent' }}>
         {threads.length === 0 && (
@@ -181,6 +190,7 @@ export default function ThreadList({
             thread={t}
             pinNumber={store.getPinNumber(t.id)}
             onClick={() => onSelectThread(t.id)}
+            focused={focusedThreadId === t.id}
           />
         ))}
 

frontend/src/components/feedback/ThreadListItem.tsx

@@ -10,15 +10,18 @@ import {
   STATUS_RESOLVED,
   BORDER,
   HOVER_BG,
+  FOCUSED_BG,
+  ACCENT,
 } from './feedbackStyles';
 
 interface ThreadListItemProps {
   thread: Thread;
   pinNumber: number;
   onClick: () => void;
+  focused?: boolean;
 }
 
-export default function ThreadListItem({ thread, pinNumber, onClick }: ThreadListItemProps) {
+export default function ThreadListItem({ thread, pinNumber, onClick, focused }: ThreadListItemProps) {
   const firstComment = thread.comments[0];
   const isResolved = thread.status === 'resolved';
 
@@ -30,9 +33,11 @@ export default function ThreadListItem({ thread, pinNumber, onClick }: ThreadLis
         borderBottom: `1px solid ${BORDER}`,
         cursor: 'pointer',
         transition: 'background 0.1s ease',
+        background: focused ? FOCUSED_BG : 'transparent',
+        borderLeft: focused ? `2px solid ${ACCENT}` : '2px solid transparent',
       }}
-      onMouseEnter={(e) => (e.currentTarget.style.background = HOVER_BG)}
+      onMouseEnter={(e) => { if (!focused) e.currentTarget.style.background = HOVER_BG; }}
-      onMouseLeave={(e) => (e.currentTarget.style.background = 'transparent')}
+      onMouseLeave={(e) => { if (!focused) e.currentTarget.style.background = 'transparent'; }}
     >
       {/* Row 1: author circle + name + timestamp */}
       <div style={{ display: 'flex', alignItems: 'center', gap: '8px', marginBottom: '6px' }}>

frontend/src/components/feedback/feedbackStyles.ts

@@ -17,6 +17,8 @@ export const INPUT_BORDER = '#26262c';
 export const INPUT_BORDER_FOCUS = '#4a9eff44';
 export const HOVER_BG = '#16161a';
 export const FILTER_ACTIVE_BG = '#1e1e24';
+export const FOCUSED_BG = 'rgba(74, 158, 255, 0.06)';
+export const FOCUSED_BORDER = 'rgba(74, 158, 255, 0.2)';
 
 // Shared panel container style
 export const panelContainerStyle: React.CSSProperties = {