- Add database-first lookup for equipment/drawing number auto-fill when
reopening previously exported files
- Remove prefix prepending for named parts (only use prefix for PT## BOM items)
- Create ExportRecord/BomItem/CutTemplate chains for Part and Assembly
exports, not just Drawings
- Add auto-incrementing item numbers across drawing numbers
- Add content hashing (SHA256) for DXF and PDF versioning with
stash/archive pattern
- Add EF Core initial migration for ExportDxfDb
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>