feat(docx): add hi-fidelity XML injections for tables, styles, lists, and sections; extend tools and tests

- Add feature flags: hi-fidelity-tables, hi-fidelity-styles, hi-fidelity-lists, hi-fidelity-sections
- Tables: inject true w:gridSpan/w:vMerge and w:tblGrid widths via post-build XML when enabled
- Styles: ensure TableHeader style in styles.xml; tag first row when headers present
- Lists: robust numbering.xml for ordered/unordered with multi-level definitions
- Sections: write tail w:sectPr with page size/orientation/margins
- Tools: expose new operations (sections, list items, images, hyperlinks, props, redaction, storage)
- Converters: add preference-aware methods for hi-fidelity export paths; HTML export tool
- Tests: add golden XML assertions gated by feature flags; keep default build green

This enables high-fidelity DOCX output while keeping pure-Rust paths by default.

tests/converter_tests.rs

@@ -25,6 +25,9 @@ fn setup_test_handler_with_content() -> (DocxHandler, String, TempDir) {
         ],
         headers: Some(vec!["Product".to_string(), "Price".to_string(), "Quantity".to_string()]),
         border_style: Some("single".to_string()),
+        col_widths: None,
+        merges: None,
+        cell_shading: None,
     };
     handler.add_table(&doc_id, table_data).unwrap();