PH-CON-001

Name: Mass conservation violation

Severity: error

Input modes: adapter+dump

Scope separation (read first): PH-CON-001 validates the production rule’s ability to measure integral conservation drift on analytically controlled source-free snapshots. It does not certify the accuracy of a heat-equation time integrator. The F2 fixture is explicitly analytical-snapshot (u = cos(2πx) cos(2πy) · exp(−8π²κt), exact solution of 2D periodic heat with zero spatial mean at all t), not a numerically-evolved FD solution.

Heat mass conservation check: for source-free periodic heat equation, total mass ∫_Ω u dV is invariant in t. Rule emits max_t |M(t) − M(0)| / max(|M(0)|, ‖u_0‖_{L¹}); shipped-default relative threshold 1e-4.