Add Payap University land as a site candidate

Payap University (Chiang Mai) is interested in leasing land to the
project; a pharmaceutical facility is under construction on the same land.

New docs/site-candidates.md puts the three options side by side (Mueang
Chi lease, Northern Region Industrial Estate, Payap) with the public facts
on Payap (Mae Khao campus on the Chiang Mai-Lampang superhighway, bought
as low-lying land, ~275 acres; Faculty of Pharmacy cosmetics production
facility tendered July 2024; RPAH cannabis/herbal bioreactor centre), why
it is attractive (5 km from the old city, a university partner with music,
pharmacy and labs, production already being built there) and the checks
that could rule it out, in order: zoning for pressing, boiler and later
electroplating; whether the university can lease to a company; the GMP
neighbour's sensitivity to our emissions (argues against biomass steam
there); flooding; plot fit; galvanics consent. Questions for the next
meeting listed. Nothing re-sited: model, RFQ and site code stay on
Mueang Chi until a plot is known.

README (intro, bullet, layout), roadmap item 9 and the lease fork in
project-timeline link to it.

README.md

@@ -1,10 +1,11 @@
 # CNX Vinyl / Poy Records
 
 A vinyl record factory in planning for the Chiang Mai area of northern
-Thailand (site candidates include Lamphun and Lampang provinces). This
-repository is the source of truth for the project: planning documents and
-cost data today. As the factory takes shape it will also hold the data and
-software used to run it.
+Thailand (site candidates include Lamphun and Lampang provinces and, since
+October 2026, Payap University land in Chiang Mai). This repository is
+the source of truth for the project: planning documents and cost data
+today. As the factory takes shape it will also hold the data and software
+used to run it.
 
 ## Team
 
@@ -139,6 +140,10 @@ The detail lives in dedicated documents:
 - [Project timeline](docs/project-timeline.md): the calendar from today to
   first paying release, the BOI-to-machinery critical path, and where the
   float actually sits
+- [Site candidates](docs/site-candidates.md): the land options side by
+  side (the Mueang Chi lease, the Northern Region Industrial Estate, and
+  Payap University's offer of land next to a pharmaceutical facility under
+  construction) and what has to be checked before any of them is chosen
 - [Project scale](docs/scale.md): rough numbers for everything on one page:
   output capacity, building area, land, electrical demand, solar and
   storage, steam and fuel, headcount, and money cross-references
@@ -191,6 +196,7 @@ docs/
 ├── quality-automation.md  Stamper metrology and layered record QC
 ├── roadmap.md             Next steps in dependency order
 ├── scale.md               Rough project sizing on one page
+├── site-candidates.md     Land options and the checks before choosing
 ├── sustainability.md      Energy, water, materials commitments
 ├── traceability.md        Process logging and per-order traceability
 └── worker-safety.md       Training, clean rooms, PPE