fix: add touch event support for highlight creation on mobile

src/components/ContentPanel.tsx

@@ -74,7 +74,7 @@ const ContentPanel: React.FC<ContentPanelProps> = ({
     followedPubkeys
   })
 
-  const { contentRef, handleMouseUp } = useHighlightInteractions({
+  const { contentRef, handleSelectionEnd } = useHighlightInteractions({
     onHighlightClick,
     selectedHighlightId,
     onTextSelection,
@@ -138,7 +138,8 @@ const ContentPanel: React.FC<ContentPanelProps> = ({
               ref={contentRef} 
               className="reader-markdown" 
               dangerouslySetInnerHTML={{ __html: finalHtml }}
-              onMouseUp={handleMouseUp}
+              onMouseUp={handleSelectionEnd}
+              onTouchEnd={handleSelectionEnd}
             />
           ) : (
             <div className="reader-markdown">
@@ -152,7 +153,8 @@ const ContentPanel: React.FC<ContentPanelProps> = ({
             ref={contentRef} 
             className="reader-html" 
             dangerouslySetInnerHTML={{ __html: finalHtml || html || '' }}
-            onMouseUp={handleMouseUp}
+            onMouseUp={handleSelectionEnd}
+            onTouchEnd={handleSelectionEnd}
           />
         )
       ) : (

src/hooks/useHighlightInteractions.ts

@@ -56,8 +56,8 @@ export const useHighlightInteractions = ({
     }
   }, [selectedHighlightId])
 
-  // Handle text selection
-  const handleMouseUp = useCallback(() => {
+  // Handle text selection (works for both mouse and touch)
+  const handleSelectionEnd = useCallback(() => {
     setTimeout(() => {
       const selection = window.getSelection()
       if (!selection || selection.rangeCount === 0) {
@@ -76,6 +76,6 @@ export const useHighlightInteractions = ({
     }, 10)
   }, [onTextSelection, onClearSelection])
 
-  return { contentRef, handleMouseUp }
+  return { contentRef, handleSelectionEnd }
 }