Integrate SmartSpellChecker into build-grid finalization

SmartSpellChecker now runs during grid build (not just LLM review),
so corrections are visible immediately in the grid editor.

Language detection per column:
- EN column detected via IPA signals (existing logic)
- All other columns assumed German for vocab tables
- Auto-detection for single/two-column layouts

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

klausur-service/backend/grid_editor_api.py

@@ -1835,6 +1835,49 @@ async def _build_grid_core(
                 if fixed != text:
                     cell["text"] = fixed
 
+    # --- SmartSpellChecker: language-aware OCR correction on all cells ---
+    try:
+        from smart_spell import SmartSpellChecker
+        _ssc = SmartSpellChecker()
+        spell_fix_count = 0
+
+        # Determine language per column:
+        # en_col_type was already detected (column with IPA = English).
+        # All other content columns are assumed German for vocab tables.
+        # For single/two-column layouts, use auto-detection.
+        for z in zones_data:
+            zone_cols = z.get("columns", [])
+            for cell in z.get("cells", []):
+                text = cell.get("text", "")
+                if not text or not text.strip():
+                    continue
+                ct = cell.get("col_type", "")
+                if not ct.startswith("column_"):
+                    continue
+
+                # Determine language for this cell
+                if total_cols >= 3 and en_col_type:
+                    lang = "en" if ct == en_col_type else "de"
+                elif total_cols <= 2:
+                    lang = "auto"  # auto-detect for non-vocab layouts
+                else:
+                    lang = "auto"
+
+                result = _ssc.correct_text(text, lang=lang)
+                if result.changed:
+                    cell["text"] = result.corrected
+                    spell_fix_count += 1
+
+        if spell_fix_count:
+            logger.info(
+                "build-grid session %s: SmartSpellChecker fixed %d cells",
+                session_id, spell_fix_count,
+            )
+    except ImportError:
+        logger.debug("SmartSpellChecker not available in build-grid")
+    except Exception as e:
+        logger.warning("SmartSpellChecker error in build-grid: %s", e)
+
     # --- Debug: log cell counts per column before empty-column removal ---
     for z in zones_data:
         if z.get("zone_type") == "content":