Plant assistant mockup: operator, management, sales

docs/plant-assistant.html (test site /demos/plant-assistant/): the
plant assistant on vinyl-ai as three roles see it. Operator at the C1
press kiosk in Thai or English with push to talk (non-fill rejects
explained from cycle rows, lot change and press hall humidity, the
stamper change procedure quoted from the approved version, a lot on
hold, a refused price question, a safety question answered word for
word); management at a desk (output and yield per press against the
plan basis, steam per record against scale.md, orders at risk, the
weekly note, payroll refused); sales on a phone (order status and ship
window, repress feasibility from archived mothers and the standby
calendar, repress leads, a test pressing status, fans' addresses
refused). Each answer carries numbered sources; the side panel shows
the tool calls (ERPNext as the asker's role, the PostgreSQL replica,
VictoriaMetrics, documents, event log) on premises with the internet
not used; action buttons create drafts only. Deep links
#role=<role>&q=<id>, light and dark theme. Invented data; names match
the factory console demo.

plant-assistant.md: mockup link; sales and customer service row in
"Who asks what"; sales drafts (quotation, CRM opportunity, message).
README, site index and site/build.sh link and publish the page.

site/build.sh

@@ -25,6 +25,7 @@ DEMOS=(
 	"docs/artist-order.html demos/artist-order/index.html"
 	"docs/make-a-record.html demos/make-a-record/index.html"
 	"docs/factory-console.html demos/factory/index.html"
+	"docs/plant-assistant.html demos/plant-assistant/index.html"
 )
 for entry in "${DEMOS[@]}"; do
 	read -r src dst <<<"$entry"