fix(ocr-review): add pipe→1 as valid OCR correction in _is_spurious_change

Extend _OCR_CHAR_MAP to treat '|' as a possible misread of digit '1'
in addition to letters l/L/i/I. Fixes cases like 'cross = |. Kreuz'
→ 'cross = 1. Kreuz' (numbered list prefix) being rejected.

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

klausur-service/backend/cv_vocab_pipeline.py

@@ -5487,8 +5487,8 @@ def _is_spurious_change(old_val: str, new_val: str) -> bool:
         '6': set('gG'),
         '8': set('bB'),
         # Non-letter symbols mistaken for letters
-        '|': set('lLiI'),   # pipe → lowercase l or capital I
-        'l': set('iI|'),    # lowercase l → capital I (and reverse)
+        '|': set('lLiI1'),  # pipe → lowercase l, capital I, or digit 1
+        'l': set('iI|1'),   # lowercase l → capital I (and reverse)
     }
     has_valid_fix = False
     if len(old_val) == len(new_val):