SU(3) triangle Galerkin packet exact certificate
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kappa_cof = 17/10 - sqrt(1671)/30
kappa_cof ≈ 0.337404437602020271915329046588
single-edge extraction = 19/36
strict-flux exact packet gap = 11/9
twisted-flux exact packet gap = (12-cos(2*pi/9))/9 ≈ 1.24821728409789132942195637216
exact proof chain: kappa_cof < 2/5 < 11/9 <= packet gap
All matrix identities and characteristic-polynomial checks passed.
