feat: EffectProfile::meet() — the greatest-lower-bound, mirror of join() - #33
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Where join() composes upward (the more dangerous of each axis, so a ceiling
covers both), meet() composes downward (the safer), so the result can only lower
and never raises any axis. It is the primitive a structural counter rests on: a
human tightening a gated call's envelope ("only if reversible / only Read")
yields the tightened ceiling meet(ceiling, P_human), safe because a meet is <=
both operands on every axis.
Preserves the profile invariants: a no-mutation meet clamps subject to None
(None <= every subject, still a GLB); a meet that reaches Guaranteed carries the
rollback contract from whichever side declared it. The "never raises any axis"
property is tested as an invariant across every profile pair (greenhouse
decisions/0066).
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Where
join()composes upward (the more dangerous of each axis, so a ceiling covers both),meet()composes downward (the safer), so the result can only lower and never raises any axis.It is the primitive a structural counter rests on: a human tightening a gated call's envelope ("only if reversible / only Read") yields the tightened ceiling
meet(ceiling, P_human), safe precisely because a meet is<=both operands on every axis. That "never raises" is the whole safety claim, so it's tested as an invariant across every profile pair, not an example.Preserves the two profile invariants: a no-mutation meet clamps subject to
None(None <=every subject, still a GLB); a meet reachingGuaranteedcarries the rollback contract from whichever side declared it.Frame: greenhouse
decisions/0066(the first piece of the structural-counter tier; the gate adjudication that consumes it is a separate slice). Ships as a command minor.