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.

README.md

@@ -282,6 +282,10 @@ docs/
 ├── cnx_vinyl_parametric_payap-iso.png Isometric view of the Payap model
 ├── cnx_vinyl_parametric_payap-office.png Office building floor plans
 ├── cnx_vinyl_parametric_payap-block.png Finishing and print block plans
+├── cnx_vinyl_parametric_payap_parts.FCStd  Payap model in Part/Draft: roof, PV, parking canopies
+├── cnx_vinyl_parametric_payap_parts.png     Isometric view of the parts model
+├── cnx_vinyl_parametric_payap_parts-top.png Top view of the parts model
+├── CNX_apply_Params.FCMacro Pushes Params edits to the model (FreeCAD 26.3 RC1)
 ├── crane-workshop-tours.md Overhead crane, workshop, visitor corridor
 ├── digital-factory.md     Data platform, NixOS/Clan fleet, acquisition, app
 ├── facility-security.md   Security, HVAC, fire and life safety, compliance