Add the cnxvinyl.lol test site with a Gitea deploy workflow

site/ builds the internal test site: public/ served as is (landing page,
robots.txt, static sites) plus demo pages copied out of docs/ (the plant
operation page at /demos/plant-operation/). build.sh fails on dead
internal links and stamps version.txt.

.gitea/workflows/deploy-site.yml rsyncs site/dist to the buildfor.life
web server with the blog's two-directory rename swap, checks version.txt
on the server, purges Cloudflare when a token is set, and checks the
public URL. Secret names match the blog's workflow.

site/Caddyfile is the virtual host to append on s1 (noindex everywhere,
Cloudflare-only like the blog apex, www redirect). site/README.md has the
one-time setup: DNS, Caddy, web root, secrets, runner.

README.md

@@ -119,6 +119,10 @@ The detail lives in dedicated documents:
   and the material lab through extruder, press, trim, optical inspection,
   finishing, packaging and fulfillment, with the metal path, utilities and
   energy alongside; open it in a browser, every station is clickable
+- [Test site](site/README.md): `site/` builds https://cnxvinyl.lol/, the
+  internal test site with demo pages from `docs/` (the plant operation
+  page first) and any static site we want to share by link; Gitea Actions
+  deploys it to the buildfor.life web server on every push that touches it
 - [Production timeline](docs/production-timeline.md): how long an order
   takes stage by stage, launch vs mature configuration, the repress fast
   path, and what lead time can honestly be quoted to a customer
@@ -166,6 +170,7 @@ docs/
 ├── 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
+├── plant-operation.html   Animated plant overview (simulated SCADA)
 ├── process-flow.md        Audio file to delivered record, with all checks
 ├── production-timeline.md Order turnaround, stage by stage
 ├── project-timeline.md    Calendar to first paying release, critical path
@@ -175,6 +180,13 @@ docs/
 ├── sustainability.md      Energy, water, materials commitments
 ├── traceability.md        Process logging and per-order traceability
 └── worker-safety.md       Training, clean rooms, PPE
+site/                      Internal test site https://cnxvinyl.lol/
+├── public/                Served as is: landing page, static sites
+├── build.sh               Builds site/dist: public/ plus demo pages from docs/
+├── Caddyfile              Virtual host for the web server (applied by hand)
+└── README.md              Build, deploy and one-time setup
+.gitea/workflows/
+└── deploy-site.yml        Builds site/ and deploys it on push to master
 ```
 
 Vendor PDFs and spreadsheets are primary sources and reflect the state of