Plan the overhead crane, maintenance workshop and visitor corridor

New docs/crane-workshop-tours.md: a 5 t single-girder EOT crane over the
whole production compartment (stops at the warehouse fire wall), a
machine door and crane-served workshop/machine bay at the ramp end, and
a glazed ground-level visitor corridor along the car-park elevation with
stations in process order, its own air and acoustic glazing so tours
need no PPE. Covers what each changes in the shell (crane-ready frame,
hook height under the 7.0 m eave, no full-height cross walls in the
crane zone, room lids and crane hatches), safety, costs and open
decisions.

Propagated: construction RFQ (crane-ready frame, new section 1c, machine
door, accessible 1:12 entrance now required), scale zone table (+210 to
280 m2, total ~1,400 to 2,000 m2), facility security, worker safety,
roadmap items 9 and 15, total investment added-scope table, README.

docs/facility-security.md

@@ -38,15 +38,20 @@ option per room.
 - **Access control**: zoned, not just at the gate. Minimum zones: general
   production, galvanics clean room (controlled access is already a safety
   requirement), chemical storage, master/stamper archive, server/IT room,
-  finished goods and shipping. Badge or biometric, with logs.
+  finished goods and shipping, and the visitor corridor. Badge or
+  biometric, with logs.
 - **CCTV**: entrances, perimeter, loading dock, production floor, chemical
   storage, archive. Retention policy to be defined; Thai PDPA (personal data
   protection) applies to camera footage of staff and visitors.
 - **Intrusion alarm** with monitoring, covering off-hours.
 - **Perimeter and lighting**: fencing appropriate to the site, lit
   approaches and parking.
-- **Visitor management**: sign-in, escort rules, PPE issue at entry, no
-  unaccompanied access to production or galvanics.
+- **Visitor management**: sign-in, escort rules, no unaccompanied access to
+  production or galvanics. Tours run through the glazed visitor corridor
+  ([crane, workshop and tours](crane-workshop-tours.md)), which keeps
+  visitors out of noise, dust and plating air and so needs no PPE; anyone
+  who goes onto the floor itself is escorted and issued PPE at entry as
+  before.
 
 ## Protecting the irreplaceable