Fix garbled IPA detection for bracket-notation like [n, nn] and [1uedtX,1]

- Detect bracketed text without real IPA symbols as garbled OCR phonetics
- Allow IPA continuation fix even when other columns have content (for rows
  where EN cell is clearly garbled bracketed IPA)
- Strip parenthetical grammar annotations like (no pl) from headword before
  IPA lookup in fix_ipa_continuation_cell

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

klausur-service/backend/cv_ocr_engines.py

@@ -993,6 +993,18 @@ def _text_has_garbled_ipa(text: str) -> bool:
     it must only insert IPA to *replace* garbled phonetics that are already
     in the text — never to ADD phonetics where none existed on the page.
     """
+    # Bracketed text that doesn't contain valid IPA symbols is garbled OCR
+    # of a phonetic transcription, e.g. "[n, nn]" or "[1uedtX,1]".
+    stripped = text.strip()
+    if stripped.startswith('[') and stripped.endswith(']'):
+        inner = stripped[1:-1]
+        # Real IPA brackets contain IPA symbols (ˈˌəɪɛɒʊʌæɑɔʃʒθðŋ)
+        if not any(c in inner for c in 'ˈˌəɪɛɒʊʌæɑɔʃʒθðŋ'):
+            # Not a valid dictionary-style bracket like "(no pl)" — those
+            # use parentheses, not square brackets.  Square brackets with
+            # no IPA chars are garbled phonetics.
+            return True
+
     for w in text.strip().split():
         # Skip delimiters and very short tokens
         if len(w) <= 1 or w in ('–', '—', '-', '/', '|', ',', ';'):
@@ -1238,8 +1250,10 @@ def fix_ipa_continuation_cell(
     if not IPA_AVAILABLE or not garbled_text or not headword_text:
         return garbled_text
 
-    # Strip existing IPA brackets from headword text
-    clean_hw = re.sub(r'\[[^\]]*\]', '', headword_text).strip()
+    # Strip existing IPA brackets and parenthetical grammar annotations
+    # like "(no pl)", "(sth)", "(sb)" from headword text
+    clean_hw = re.sub(r'\[[^\]]*\]', '', headword_text)
+    clean_hw = re.sub(r'\([^)]*\)', '', clean_hw).strip()
     if not clean_hw:
         return garbled_text