Add quality automation spec: stamper metrology and layered record QC

- Keyence-class instrument stack for father/mother/stamper analysis
  (VK-X confocal sampled zones, VR-6000 wide-area, XRF thickness) with
  genealogy integration via middleware
- Three-layer pressed-record QC: 100% inline optical inspection,
  per-cycle press telemetry, sampled automated audio comparison
- Honest limits documented: no turnkey products exist for the optical
  and audio layers; 100% audio QC impossible at press speed

docs/traceability.md

@@ -21,7 +21,8 @@ For any order, the customer can follow the full chain:
    parameters (temperatures, pressures, cycle times), PVC compound lot and
    virgin/recycled mix, label lot
 6. **Quality control**: test pressing approvals, inspection results, reject
-   counts and reasons
+   counts and reasons (the automated instrument layers feeding this are
+   specified in [quality automation](quality-automation.md))
 7. **Finishing and packaging**: trimming, sleeving, carton lot, packaging
    partner batch
 8. **Fulfillment**: warehouse location, shipment or dropshipping consignment,