Fix hyphen-join: strip trailing punctuation from continuation word

The next-row word "künden," had a trailing comma, causing dictionary
lookup to fail for "verkünden,". Now strips .,;:!? before joining.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

klausur-service/backend/cv_gutter_repair.py

@@ -161,6 +161,9 @@ class GutterSuggestion:
 # Core repair logic
 # ---------------------------------------------------------------------------
 
+_TRAILING_PUNCT_RE = re.compile(r'[.,;:!?\)\]]+$')
+
+
 def _try_hyphen_join(
     word_text: str,
     next_word_text: str,
@@ -168,10 +171,15 @@ def _try_hyphen_join(
 ) -> Optional[Tuple[str, str, float]]:
     """Try joining two fragments with 0..max_missing interpolated chars.
 
+    Strips trailing punctuation from the continuation word before testing
+    (e.g. "künden," → "künden") so dictionary lookup succeeds.
+
     Returns (joined_word, missing_chars, confidence) or None.
     """
     base = word_text.rstrip("-").rstrip()
-    continuation = next_word_text.lstrip()
+    # Strip trailing punctuation from continuation (commas, periods, etc.)
+    raw_continuation = next_word_text.lstrip()
+    continuation = _TRAILING_PUNCT_RE.sub('', raw_continuation)
 
     if not base or not continuation:
         return None