Strengthen text-layer debug + log highlight render path

The first cut of "Debug text layer" only painted direct `<span>`
children of `.textLayer`. PDF.js 4.x wraps marked content in nested
spans/divs, so the entire selectable area wasn't visible — making it
hard to tell whether a region is "no text layer at all" vs. "text
layer present but small/dense".

Changes:
- CSS now targets every descendant of `.textLayer`, dims the canvas
  underneath, and outlines the `.textLayer` container itself so its
  full extent is obvious.
- TextHighlight rectangles flip to green in debug mode so saved
  highlights don't get washed out by the debug yellow.
- The viewer now logs:
    [ce] viewer highlights        — which annotations rendered, which
                                    were skipped, with rects + page
    [ce] scrollToAnnotation       — whether the target was found in
                                    the highlights array when an
                                    activation arrived

This is the diagnostic loop for the "viewport scrolls but the
highlight doesn't appear" report — if highlight count is > 0 in the
first log but the green rectangle is off-screen, the saved rects
inherited the same text-layer misalignment that caused the partial
selection captures in the first place.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/anchor/debug-textlayer.css

@@ -11,14 +11,30 @@
  */
 
 .ce-debug-textlayer .textLayer {
-  outline: 1px dashed rgba(255, 0, 0, 0.5);
+  outline: 2px dashed rgba(255, 0, 0, 0.5);
+  background: rgba(255, 0, 0, 0.05);
 }
 
-.ce-debug-textlayer .textLayer > span,
-.ce-debug-textlayer .textLayer > br {
-  background: rgba(255, 220, 0, 0.35) !important;
+/* PDF.js 4.x wraps marked content in nested spans/divs — cover every
+   descendant so the entire selectable area is visible regardless of how
+   the renderer nested things. */
+.ce-debug-textlayer .textLayer * {
+  background: rgba(255, 220, 0, 0.45) !important;
   color: rgba(0, 0, 100, 0.85) !important;
   opacity: 1 !important;
-  /* Reveal the per-glyph span borders so misalignment is visible. */
-  outline: 1px solid rgba(0, 100, 255, 0.25);
+  outline: 1px solid rgba(0, 100, 255, 0.3);
+}
+
+/* Make the canvas-rendered layer dim so the text-layer overlay stands
+   out by contrast. */
+.ce-debug-textlayer canvas {
+  opacity: 0.35;
+}
+
+/* Make any existing TextHighlight rectangles obvious even in debug
+   mode (the highlighter's own yellow gets washed out by our debug
+   yellow). */
+.ce-debug-textlayer .TextHighlight__part {
+  background: rgba(0, 200, 0, 0.45) !important;
+  outline: 2px solid rgba(0, 120, 0, 0.7) !important;
 }

src/anchor/pdf-viewer-adapter-spike.tsx

@@ -194,21 +194,44 @@ export function PdfSpikeViewer(props: PdfSpikeViewerProps) {
 
   const highlights = useMemo<Highlight[]>(() => {
     const out: Highlight[] = [];
+    const skipped: { id: string; reason: string }[] = [];
     for (const a of storedAnnotations) {
       const h = highlightFromSelectors(a.id, a.text, a.selectors);
       if (h) out.push(h);
+      else skipped.push({ id: a.id, reason: "no PdfRectSelector / empty boundingRect" });
+    }
+    if (debugTextLayer) {
+      console.log("[ce] viewer highlights", {
+        in: storedAnnotations.length,
+        rendered: out.length,
+        rendered_detail: out.map((h) => ({
+          id: h.id,
+          page: h.position.boundingRect.pageNumber,
+          bounding: h.position.boundingRect,
+          rectCount: h.position.rects.length,
+        })),
+        skipped,
+      });
     }
     return out;
-  }, [storedAnnotations]);
+  }, [storedAnnotations, debugTextLayer]);
 
   useEffect(() => {
     if (!scrollToAnnotationId || didScroll === scrollToAnnotationId) return;
     const utils = utilsRef.current;
     const target = highlights.find((h) => h.id === scrollToAnnotationId);
+    if (debugTextLayer) {
+      console.log("[ce] scrollToAnnotation requested", {
+        id: scrollToAnnotationId,
+        utilsAvailable: !!utils,
+        targetFound: !!target,
+        knownIds: highlights.map((h) => h.id),
+      });
+    }
     if (!utils || !target) return;
     utils.scrollToHighlight(target);
     setDidScroll(scrollToAnnotationId);
-  }, [scrollToAnnotationId, highlights, didScroll]);
+  }, [scrollToAnnotationId, highlights, didScroll, debugTextLayer]);
 
   return (
     <div