Add the Payap University partnership: joint student programmes

Payap also wants to work closely with the project on new student
programmes: audio engineering (mastering, lathe cutting), IT, business
administration and more.

New docs/payap-partnership.md: why it fits (mastering/cutting engineers
are the hardest hires; Payap has music, IT, business, communication arts,
an English-language International College and pharmacy labs; the plant has
a lathe, production data and a real factory application), programme areas
mapped to the docs they draw on, and what it changes: a reason to bring
the cutting room (roadmap item 27) forward, a cutting engineer before the
students, lacquer and stylus cost of teaching, pre-release security for
customer audio, student access and safety, IT work on staging only, the
link to the Payap land, BOI R&D merit. Suggested form: MOU, internships,
short certificate courses first, degree tracks later; what to settle in
writing and questions for the next meeting.

Links from README (bullet, layout), site-candidates, roadmap item 27, the
supplier map's open training item and the BOI open items.

docs/roadmap.md

@@ -123,7 +123,8 @@ These three run in parallel and gate everything downstream:
 25. Full metrology stack and the sampled audio QC station
 26. Biomass boiler, fed by the by-then-mature coppice plus regional fuel
 27. Mastering and cutting room (can move earlier if title-services demand
-    shows up in Phase 4)
+    shows up in Phase 4, or to host the joint audio engineering programme
+    with Payap University, see [Payap partnership](payap-partnership.md))
 
 ## Standing principle