## [1.3.0] - 2026-02-23

### 🚀 New Features

Add flexible workbook detection and doc sheet support.

**Workbook Auto-Detection** (`root_marker=None`):
- Single H1 header is auto-detected as workbook root
- H1 containing `<!-- md-spreadsheet- ... -->` metadata comment is detected
- Fallback search for `# Tables` or `# Workbook`
- Sheet/table header levels auto-calculated from workbook level

**New Sheet Fields**:
- `Sheet.type`: `"table"` or `"doc"`
- `Sheet.content`: Raw markdown for doc sheets

**New Workbook Fields**:
- `Workbook.name`: Extracted from detected root marker
- `Workbook.root_content`: Captures content between workbook header and first sheet header

**Backward Compatibility**:
- Explicit `root_marker` preserves existing behavior
- `table_header_level=None` with explicit root still means "no table headers"