Add whole-factory HVAC requirement and process traceability spec

- facility-security.md: continuous temperature/humidity/PM control, zoned
  filtration, burning-season PM2.5 design point, HVAC in PV/battery sizing
- traceability.md: end-to-end per-order customer traceability, batch
  genealogy, log-at-source principles, machine data access as a
  procurement requirement

docs/sustainability.md

@@ -35,6 +35,10 @@ at 10 bar / 180 °C) and the 250 kW cooling system.
   abundant fuel), and solar-thermal pre-heating of boiler feedwater. No
   technology choice has been made yet; it will be driven by honest numbers on
   load profiles, storage, and grid backup, not by what sounds greenest.
+- Whole-factory HVAC (continuous temperature, humidity, and PM control, see
+  [facility systems](facility-security.md)) adds a major tropical-climate
+  load on top of process cooling and must be part of the PV and battery
+  sizing.
 - System sizing (kWp, storage, grid-connection model) is open until the site
   is chosen.