fix: render image description when chunk has no bbox (no broken crop)

29 image chunks have an empty bbox {}, and `fm.bbox ?? default` doesn't catch
an empty object, so the crop URL got w=undefined → /api/crop 400 → broken-image
icon. Now validate bbox (w/h > 0); without it, render the image's textual
description instead of requesting an impossible crop.

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

web/components/doc-renderer-v2.tsx

@@ -141,6 +141,33 @@ function ChunkCard({
 
   // Image chunks: render crop inline
   if (fm.type === "image" || fm.image_type) {
+    const hasValidBbox =
+      bbox &&
+      typeof bbox.w === "number" && typeof bbox.h === "number" &&
+      typeof bbox.x === "number" && typeof bbox.y === "number" &&
+      bbox.w > 0 && bbox.h > 0;
+
+    // No crop coordinates → don't request a broken crop (400). Render the
+    // image's textual description so the content is still surfaced.
+    if (!hasValidBbox) {
+      const descEn = fm.image_description_en || content_en;
+      const descPt = fm.image_description_pt_br || content_pt;
+      if (!descEn && !descPt) return null;
+      return (
+        <figure className="relative my-8" id={fm.chunk_id}>
+          {anchor}
+          <div className="border border-[rgba(0,255,156,0.20)] bg-[#0a121e] rounded p-4 text-sm text-[#c8d4e6]">
+            <div className="font-mono text-[10px] text-[#7fdbff] mb-2">
+              🖼 {fm.chunk_id} · p{fm.page}
+              {fm.image_type ? ` · ${fm.image_type}` : ""} · descrição (sem recorte)
+            </div>
+            {showEn && descEn && <p className="mb-1"><b>EN:</b> {descEn}</p>}
+            {showPt && descPt && <p><b>PT-BR:</b> {descPt}</p>}
+          </div>
+        </figure>
+      );
+    }
+
     const cropUrl =
       `/api/crop?doc=${encodeURIComponent(docId)}` +
       `&page=${fm.page}&x=${bbox.x}&y=${bbox.y}&w=${bbox.w}&h=${bbox.h}&w_px=800`;