fix: preserve panel labels and figure_inner_text in post-reference backmatter zone

paperforge/worker/ocr_document.py

@@ -4682,6 +4682,12 @@ def normalize_document_structure(
                     new_role="media_asset",
                     reason="image/media block in post_reference_backmatter_zone promoted to media_asset",
                 )
+        # ponytail: panel_label + figure_inner_text guard; if other specialized roles
+        # appear in backmatter zone, extend this list
+        if block.get("marker_signature", {}).get("type") == "panel_label":
+            continue
+        if block.get("role") == "figure_inner_text":
+            continue
         elif role not in _BACKMATTER_NON_BODY_ROLES:
             old_role = block.get("role")
             if old_role != "backmatter_body":

tests/test_ocr_layout_first_regressions.py

@@ -143,3 +143,21 @@ def test_keep_formal_caption_seed_for_numbered_display_legend() -> None:
     }
 
     assert _should_keep_formal_caption_seed(block) is True
+
+
+def test_panel_label_in_post_ref_zone_not_converted_to_backmatter() -> None:
+    """Panel labels like (a) in post_reference_backmatter_zone stay figure_inner_text.
+
+    Regression: guard in normalize_document_structure prevents backmatter
+    normalization from overwriting figure_inner_text role.
+    """
+    from paperforge.worker.ocr_roles import assign_block_role
+
+    block = {
+        "block_label": "text",
+        "block_content": "(a)",
+        "block_bbox": [90, 90, 120, 120],
+        "page": 10,
+    }
+    role = assign_block_role(block, page_blocks=[], page_width=1200, page_height=1600)
+    assert role.role == "figure_inner_text"