Address bot review feedback on PR #6

* Match prior overlay measurements by LineRef coordinates instead of
  object identity, so parents that recreate refs across renders don't
  flicker the highlight boxes.
* Drop the dead isHoveringRef guard from pierre-diff-viewer since the
  hover utility is disabled.
* Default useIsMac SSR snapshot to false to avoid a hydration mismatch
  on non-Mac systems.
* Fix the fixture patch hunk header so its line counts match the body.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: dastratakos

web/src/App.tsx

@@ -12,7 +12,7 @@ const SAMPLE_PATCH = `diff --git a/src/greet.ts b/src/greet.ts
 index 1111111..2222222 100644
 --- a/src/greet.ts
 +++ b/src/greet.ts
-@@ -1,5 +1,7 @@
+@@ -1,3 +1,6 @@
 -export function greet(name: string) {
 -  return "Hello, " + name + "!";
 +export function greet(name: string): string {

web/src/components/chapter/hunk-highlight-overlay.tsx

@@ -114,9 +114,9 @@ function measureLineRange(
 }
 
 /**
- * Matching by ref identity preserves prior measurements when the current
- * measurement fails (shadow root missing, line not yet rendered) and avoids
- * index-aliasing bugs when the refs array changes between renders.
+ * Matching by coordinates (not object identity) preserves prior measurements
+ * even when the parent recreates LineRef objects between renders, while still
+ * avoiding the index-aliasing bugs you'd get from matching by array position.
  */
 function measureAll(
   refs: readonly LineRef[],
@@ -130,7 +130,14 @@ function measureAll(
       ? measureLineRange(shadowRoot, ref, container, containerRect)
       : null;
     if (measured) return { ref, box: measured };
-    const prevBox = prev.find((p) => p.ref === ref)?.box ?? null;
+    const prevBox =
+      prev.find(
+        (p) =>
+          p.ref.filePath === ref.filePath &&
+          p.ref.side === ref.side &&
+          p.ref.startLine === ref.startLine &&
+          p.ref.endLine === ref.endLine,
+      )?.box ?? null;
     return { ref, box: prevBox };
   });
 }

web/src/components/chapter/pierre-diff-viewer.tsx

@@ -118,17 +118,15 @@ export function PierreDiffViewer({
 
   const diffContainerRef = useRef<HTMLDivElement>(null);
 
-  const isHoveringRef = useRef(false);
-
-  // Suppress onLineSelected during hover — Pierre fires it when the selectedLines
-  // prop changes, but hover highlights shouldn't trigger any selection logic.
   const guardedOnLineSelected = useCallback(
     (range: SelectedLineRange | null) => {
-      if (isHoveringRef.current) return;
       if (!range) {
         onLineSelected?.(null);
         return;
       }
+      // Pierre's drag-to-select emits `{ start: anchor, end: currentLine }`
+      // without ordering them, so dragging upward produces a range where
+      // start > end — normalize so downstream consumers see ascending bounds.
       const normalized: SelectedLineRange =
         range.start <= range.end
           ? range

web/src/lib/use-is-mac.ts

@@ -18,7 +18,7 @@ function getSnapshot() {
 }
 
 function getServerSnapshot() {
-  return true;
+  return false;
 }
 
 export function useIsMac() {