Update grid-to-pipe table converter with alignment support

- Properly preserves left/center/right alignment from grid tables
- Added --check mode for pre-commit warning
- Added book-check-grid-tables hook to warn about grid tables
- Grid tables should be converted to pipe for better inline Python support

.pre-commit-config.yaml

@@ -190,6 +190,14 @@ repos:
         pass_filenames: false
         files: ^book/quarto/contents/.*\.qmd$
 
+      - id: book-check-grid-tables
+        name: "Book: Warn about grid tables (prefer pipe tables)"
+        entry: python book/tools/scripts/utilities/convert_grid_to_pipe_tables.py --check
+        language: python
+        pass_filenames: true
+        files: ^book/quarto/contents/.*\.qmd$
+        verbose: true
+
       - id: book-validate-part-keys
         name: "Book: Validate part keys"
         entry: python book/tools/scripts/utilities/validate_part_keys.py