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/roadmap.md

@@ -50,8 +50,10 @@ These three run in parallel and gate everything downstream:
 9. **Site selection**: candidate buildings/plots in Lamphun and Lampang
    (Northern Region Industrial Estate first for its shared effluent
    treatment and licensing simplicity), screened against the
-   [scale requirements](scale.md): 6 to 8 rai, 1,200 to 1,700 m² single
-   story, multiple tons per m² slab, 500 to 1,000 kVA connection
+   [scale requirements](scale.md): 6 to 8 rai, 1,400 to 2,000 m² single
+   story (including the workshop and visitor corridor), multiple tons per
+   m² slab, 500 to 1,000 kVA connection, and a frame able to carry an
+   overhead crane
 
 ## Phase 2: Commit (after BOI certificate and validated pricing)
 
@@ -71,7 +73,11 @@ These three run in parallel and gate everything downstream:
 
 15. Building fit-out: slab verification, HVAC, clean zones, utilities,
     solar and BESS installation, security systems per
-    [facility-security.md](facility-security.md)
+    [facility-security.md](facility-security.md), and the overhead crane,
+    maintenance workshop and visitor corridor per
+    [crane-workshop-tours.md](crane-workshop-tours.md) (the crane-ready
+    frame itself is in the construction RFQ, so it is decided before the
+    shell is ordered)
 16. Machinery installation and vendor commissioning (Newbilt on-site
     commissioning is mandatory for warranty; budget per the service rate
     card)