Fix IPA:Aus — strip all brackets before skipping IPA block

When ipa_mode=none, the entire IPA processing block was skipped,
including the bracket-stripping logic. Now strips ALL square brackets
from content columns BEFORE the skip, so IPA:Aus actually removes
all IPA from the display.

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

klausur-service/backend/grid_editor_api.py

@@ -961,6 +961,21 @@ async def _build_grid_core(
     ipa_target_cols: set = set()
     all_content_cols: set = set()
     skip_ipa = (ipa_mode == "none")
+
+    # When ipa_mode=none, strip ALL square brackets from ALL content columns
+    if skip_ipa:
+        _SQUARE_BRACKET_RE_NONE = re.compile(r'\s*\[[^\]]+\]')
+        for cell in all_cells:
+            ct = cell.get("col_type", "")
+            if not ct.startswith("column_"):
+                continue
+            text = cell.get("text", "")
+            if "[" in text:
+                stripped = _SQUARE_BRACKET_RE_NONE.sub("", text)
+                if stripped != text:
+                    cell["text"] = stripped.strip()
+                    cell["_ipa_corrected"] = True
+
     if not skip_ipa and total_cols >= 3:
         # Detect English headword column via IPA signals (brackets or garbled).
         col_ipa_count: Dict[str, int] = {}