Plant assistant: one agent management and operators can ask

New docs/plant-assistant.md (decision, Alexander, 26 Oct 2026): an
assistant for the whole plant, asked in Thai or English at kiosks, desks
and phones, answering from the knowledge base (SOPs as ERPNext Quality
Procedures, vendor manuals on the Assets, recipes and limits, this
repository, lessons learned) and from ERPNext and the machine-data store,
with sources on every answer. Roles and questions, what it does
(explain, trace, summarise, alert context, plan vs actual, drafts) and
never does (machines, submitting, safety improvisation, seeing more than
the asker, rating operators, needing the internet). Built on Typhoon 2.5
(open weights, Apache-2.0, CPU trial first), Typhoon ASR for optional
voice, pgvector retrieval, MCP tools in cnx-factory through the one
integration layer and the PostgreSQL replica; vinyl-ai GPU server only if
needed (~250k to 300k THB, RTX 5090 Thai retail Oct 2026). Test set per
role, phasing, cost, risks, open decisions.

Mirrors: digital-factory systems and machines tables, rough cost note;
catalogue advisor becomes a role of the assistant; worker-safety
training; roadmap item 18; README bullet and layout.

README.md

@@ -195,6 +195,12 @@ The detail lives in dedicated documents:
   repo, VLAN zoning, Telegraf/MQTT acquisition source by source, QC
   instrument integration, the factory application, alerting, backup,
   security, the data clauses for every RFQ, build order and rough cost
+- [Plant assistant](docs/plant-assistant.md): an agent management and
+  operators ask in Thai or English, at a press kiosk, a desk or a phone;
+  it answers from the procedures, vendor manuals and this repository and
+  from ERPNext and the machine data, with sources on every answer, sees
+  only what the asker may see, drafts but never submits, never touches a
+  machine, and runs on site on an open-weights model
 - [Inline optical QC](docs/equipment/inline-optical-qc.md): devices for
   the 100% record inspection station (line-scan cameras with dark-field
   and transmitted light, label camera, laser warp sensors, centring
@@ -433,6 +439,7 @@ docs/
 │                          Payap rezoning route)
 ├── make-a-record.html     Artist platform investor demo (end-user flow)
 ├── payap-partnership.md   Joint student programmes with Payap University
+├── plant-assistant.md     Ask the plant: assistant on knowledge base and data
 ├── plant-operation.html   Animated plant overview (simulated SCADA)
 ├── process-flow.md        Audio file to delivered record, with all checks
 ├── production-hall-layout-sketch.FCStd  Rough BIM sketch, Mueang Chi hall (earlier fleet)