Supersedes v1.4.0-c1-two-sided as the anchor for the revised C1 paper:
this tag includes everything that tag lacked.

The C1 chain, complete: CL-031 (the general four-answer obstruction, on
an arbitrary shared state space -- Bell's Lambda, spelled SigmaSpace with
the identification stated in the docstrings) + CL-052
(c1_singlet_contextual_capstone: an explicit measurable shared-context
family on (KSigma 4, kMuPsi) reproduces the singlet -- the full P_st
table at every context -- and no global CHSH assignment is compatible
with it). Q20 discharges the paper's sections 4 and 5.1 on the exhibited
model: singletContextualModel_no_signalling (first inhabitant of
OperationalNoSignalling; measurement independence named as a premise) and
singletContextualModel_not_product (ReproducesSinglet inhabited; the
every-setting no-go exercised on an exhibited object). Honest scope in
docs/C1-FORMAL-SUPPORT.md: the outcome family is a chosen partition, not
a readout (MD-1 open); the incompatibility half constrains the four CHSH
settings only; the singlet sector is posited (SO-1).

Independent of the cosmological constant: the concept appears nowhere in
the corpus; the symbol Lambda survives only as Bell's hidden-variable
notation in the QM-side LHV bound.

Cite by this tag + commit SHA + module path + theorem name, per
docs/C1-FORMAL-SUPPORT.md.