Remove IPA continuation rows and support hyphenated word lookup

- grid_editor_api: After IPA correction, detect rows containing only
  garbled phonetics in the English column (no German translation, no
  IPA brackets inserted). These are wrap-around lines where printed
  IPA extends to the line below the headword. Remove them since the
  headword row already has correct IPA.
- cv_ocr_engines: _insert_missing_ipa now tries dehyphenated form
  as fallback (e.g. "second-hand" → "secondhand") for dictionary
  lookup, fixing IPA insertion for compound words.

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

klausur-service/backend/cv_ocr_engines.py

@@ -1026,6 +1026,9 @@ def _insert_missing_ipa(text: str, pronunciation: str = 'british') -> str:
         if clean.lower() in _GRAMMAR_BRACKET_WORDS:
             continue
         ipa = _lookup_ipa(clean, pronunciation)
+        # Fallback: try without hyphens (e.g. "second-hand" → "secondhand")
+        if not ipa and '-' in clean:
+            ipa = _lookup_ipa(clean.replace('-', ''), pronunciation)
         if ipa:
             words[i] = f"{w} [{ipa}]"
             # Strip garbled OCR phonetics after the IPA bracket.