fix: switch from ∧ to && in ZModCharges

[wdconinc]

This PR changes the ∧ to && in ZModCharges to ensure this runs in finite time with lean4.35.0-rc1 (and -rc3).

This change is necessary (after some Claude debugging) due to changes short-circuiting behavior for ∧ but not &&. These changes were introduced in leanprover/lean4#8309, leanprover/lean4#14859, and leanprover/lean4#15128, but to be honest I am not quite clear on how or why.

This does lead to build times that are smaller (than infinite...; I never got this to build for n = 6 with lean4.34.0). This may resolve the reason why leanprover-community/downstream-reports#96 was timing out (but of course doesn't address other lean4.35.0-rc1 bumps required).

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[Copilot]

Copilot review overview

🟢 Approval recommended

The single-line change is a semantically-equivalent boolean rewrite that fixes a reduction-time performance regression without altering the computed set or the dependent lemmas.

Review effort: Balanced
Findings: None

What changed in this PR

This PR addresses a build-time performance regression in the SU(5) charge-spectrum machinery. In ZModCharges, the Finset.filter predicate that selects complete, non-pheno-constrained, non-dangerous charge spectra is rewritten from a Prop-valued conjunction (∧) into a Bool-valued conjunction using decide and &&. Per the description, this restores short-circuiting during kernel/native_decide reduction under lean4.35.0-rc, turning previously non-terminating builds (notably n = 6) into finite ones. The change is semantically equivalent—A ∧ ¬B ∧ ¬C matches decide A && !decide B && !decide C—so the downstream decide/native_decide lemmas asserting specific set contents (ZModCharges_four_eq, ZModCharges_six_eq, etc.) continue to pin the same results.

Changes:

• Rewrites the ZModCharges filter predicate from ∧/¬ (Prop) to &&/!/decide (Bool) to recover short-circuiting during reduction.
• No change to the mathematical meaning of the definition or its dependent lemmas.

File	Description
Physlib/​Particles/​SuperSymmetry/​SU5/​ChargeSpectrum/​ZMod.lean	Converts the ZModCharges filter condition to a boolean expression to fix reduction-time performance while preserving the resulting Finset.

Note (non-blocking, outside the changed region): the sibling definition ZModZModCharges (lines 168–171) still uses the original ∧ pattern. It currently has no decide/native_decide lemmas depending on it, so the regression is latent there, but applying the same transformation would keep the two definitions consistent if such lemmas are added later.

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[jstoobysmith]

Closing this, as hopefully the Lean fix will ensure this works.