Payap scenario: Part/Draft model with roof, rooftop PV and PV parking canopies

New FreeCAD model docs/cnx_vinyl_parametric_payap_parts.FCStd: the Payap
scenario rebuilt from plain Part solids and Draft (arrays, labels,
dimensions) on the same Params sheet, no BIM objects, plus:

- monopitch roof 10 deg, low eave 7.0 m south, high side 11.4 m north
  (phase 1 RFQ geometry); gables and the fire wall follow the roof
- rooftop PV: 901 x 580 W placeholder modules, ~523 kWp, 17 rows in
  blocks of four with walkways, 1 m edge strip, 2.5 m clear over the
  fire wall (estimate)
- car canopy (10 bays, 72 modules) and scooter canopy (30 spaces,
  22 modules), ~54 kWp, RFQ footprints and heights
- module counts and kWp as sheet expressions; ~577 kWp in all

FreeCAD 26.3 RC1 does not propagate spreadsheet edits: CNX_apply_Params
macro touches the dependents and recomputes; parametric test (factory
length, pitch, car bays, walkway) matches the sheet counts.

site-candidates.md: roof/PV/canopy section with the export, battery and
BOI questions a 577 kWp array raises; mirrors in sustainability.md and
scale.md; README layout lines.

docs/scale.md

@@ -113,6 +113,9 @@ Staff parking is roofed, in the front yard clear of the loading route:
 canopies — dimensions per the modelled layout in the
 [construction RFQ](finance/phase1-construction-rfq.md). At 4.1 m and 3.5 m
 they sit below the main building's 7.0 m low eave, so they cannot shade it.
+Fully covered with the 580 W placeholder module the two canopies take 94
+modules (~54 kWp); see the Payap parts model in
+[site candidates](site-candidates.md#roof-pv-and-parking-canopies-part-and-draft-model-october-2026).
 
 ### Expansion headroom: a second building