- Add CableLabelData struct and RenderCable() producing 384x180 bitmap
- Cable template: HW ID, name, USB version/speed, wattage/test date
- IsCableDevice() detects cable records by name or AINotes heuristic
- T-04-07 mitigation applied: HWID format validated in RenderCable too
- All 5 cable tests pass (10 total in package)
- Add internal/labels package with LabelData struct and RenderStandard()
- QR encodes http://mac-mini.mg:8080/hw/HW-XXXXX (LBL-01)
- Label is 384x120px NRGBA, white background, basicfont text
- T-04-07 mitigation: validate HWID format before qrcode.New()
- Install github.com/skip2/go-qrcode and golang.org/x/image
- All 5 renderer tests pass
