The v143 linker refuses to emit an image with unresolved externals even
under /FORCE, so the dead offline-tool ladders in mech3.cpp
(Mech::CreateSubsystemStream / SubsystemDefaultData -- never called at
runtime, resources ship prebuilt in BTL4.RES) are compiled out behind
BT412_OFFLINE_TOOLS (default off). The exe links /FORCE:MULTIPLE only:
a genuinely unresolved symbol is now a hard link error instead of a
hidden runtime AV. No other source changes needed for v143.
Verified: clean build; solo DEV.EGG runs; two-instance loopback MP via
btconsole.py -- mesh forms, mission runs both sides, master + replicant
tick in each world. (Phase 1 of docs/BT412-ROADMAP.md)
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>