Introduce a Drawing table that tracks unique drawing numbers with their
current PDF content hash and revision counter. ExportRecord gains a
DrawingId FK. Includes a data migration to seed Drawings from existing
export records.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Add separate EquipmentNo and DrawingNo fields alongside the combined
DrawingNumber, plus a Title field for labeling exports. Updated across
Core model, DbContext, API DTOs, and ExportDXF models.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
