Fix IPA correction for dictionary pages (WIP)

- Fix Step 5h: restrict slash-IPA conversion to English headword column
  only — prevents converting "der/die/das" to "der [dər]das" in German
  columns (confirmed working)
- Fix _text_has_garbled_ipa: detect embedded apostrophes in merged
  tokens like "Scotland'skotland" where OCR reads ˈ as '
- Fix _insert_missing_ipa: detect dictionary word prefix in merged
  trailing tokens like "fictionsalans'fIkfn" → extract "fiction" with IPA
- Move en_col_type to wider scope for Step 5h access

Note: Fixes 1+2 confirmed working in unit tests but not yet applying
in the full build-grid pipeline — needs further debugging.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

klausur-service/backend/cv_ocr_engines.py

@@ -1030,6 +1030,15 @@ def _text_has_garbled_ipa(text: str) -> bool:
         # Contains IPA special characters
         if any(c in w for c in 'əɪɛɒʊʌæɑɔʃʒθðŋ'):
             return True
+        # Embedded apostrophe suggesting merged garbled IPA with stress mark.
+        # E.g. "Scotland'skotland" — OCR reads ˈ as '.
+        # Guard: apostrophe must be after ≥3 chars and before ≥3 lowercase
+        # chars to avoid contractions (don't, won't, o'clock).
+        if "'" in w and not w.startswith("'"):
+            apos_idx = w.index("'")
+            after = w[apos_idx + 1:]
+            if apos_idx >= 3 and len(after) >= 3 and after[0].islower():
+                return True
     return False
 
 
@@ -1183,6 +1192,17 @@ def _insert_missing_ipa(text: str, pronunciation: str = 'british') -> str:
                     if _lookup_ipa(clean_j, pronunciation):
                         kept.extend(words[j:])
                         break
+                # Merged token: dictionary word + garbled IPA stuck together.
+                # E.g. "fictionsalans'fIkfn" starts with "fiction".
+                # Extract the dictionary prefix and add it with IPA.
+                if clean_j and len(clean_j) >= 5:
+                    for pend in range(min(len(clean_j), 15), 2, -1):
+                        prefix_j = clean_j[:pend]
+                        prefix_ipa = _lookup_ipa(prefix_j, pronunciation)
+                        if prefix_ipa:
+                            kept.append(f"{prefix_j} [{prefix_ipa}]")
+                            break
+                    break  # rest of this token is garbled
                 # Otherwise — likely garbled phonetics, skip
             words = kept
             break

klausur-service/backend/grid_editor_api.py

@@ -858,6 +858,7 @@ async def _build_grid_core(session_id: str, session: dict) -> dict:
     # Single/two-column layouts are continuous text, not vocab tables.
     all_cells = [cell for z in zones_data for cell in z.get("cells", [])]
     total_cols = sum(len(z.get("columns", [])) for z in zones_data)
+    en_col_type = None
     if total_cols >= 3:
         # Find the column that contains IPA brackets → English headwords.
         # Count cells with bracket patterns per col_type.  The column with
@@ -872,7 +873,6 @@ async def _build_grid_core(session_id: str, session: dict) -> dict:
             if ct.startswith("column_") and '[' in txt:
                 col_bracket_count[ct] = col_bracket_count.get(ct, 0) + 1
         # Pick column with most bracket IPA patterns
-        en_col_type = None
         if col_bracket_count:
             en_col_type = max(col_bracket_count, key=col_bracket_count.get)
         else:
@@ -1105,6 +1105,10 @@ async def _build_grid_core(session_id: str, session: dict) -> dict:
     slash_ipa_fixed = 0
     for z in zones_data:
         for cell in z.get("cells", []):
+            # Only process English headword column — avoid converting
+            # German text like "der/die/das" to IPA.
+            if en_col_type and cell.get("col_type") != en_col_type:
+                continue
             text = cell.get("text", "")
             if "/" not in text:
                 continue