Hygiene B0-B1: correctness & latent traps

- Restore swallowed [Test] on EnemyAIMathTests.SlideVelocity_DegenerateNormal_DeflectsToTangent (dead regression guard for the shipped enemy-stuck-on-cover fix; now runs + passes).
- Extract shared HarvestMath.DepositYield used by ResourceHarvestSystem + MeleeComboSystem; fixes melee mining silently ignoring per-item StackMax (it hard-coded DefaultStackMax) and hoists the melee ledger-buffer fetch out of the per-target loop.
- StatMath.Apply switches on the raw byte (case (byte)ModOp.X) instead of casting to the enum inside the Bursted fold — removes the latent cross-assembly enum-in-Burst ICE trap.
- Add [Min] guards on CycleDirectorAuthoring loss-critical ints (CoreIntegrityMax>=1 so a mis-authored 0 can't bake an instant-loss core; siege sizes >=0).

456/456 EditMode tests pass.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Assets/_Project/Scripts/Simulation/Combat/StatMath.cs

@@ -28,11 +28,11 @@ namespace ProjectM.Simulation
                 var m = mods[i];
                 if (m.Target != t)
                     continue;
-                switch ((ModOp)m.Op)
+                switch (m.Op)
                 {
-                    case ModOp.Flat: flat += m.Value; break;
-                    case ModOp.PercentAdd: percentAdd += m.Value; break;
-                    case ModOp.PercentMult: percentMult *= 1f + m.Value; break;
+                    case (byte)ModOp.Flat: flat += m.Value; break;
+                    case (byte)ModOp.PercentAdd: percentAdd += m.Value; break;
+                    case (byte)ModOp.PercentMult: percentMult *= 1f + m.Value; break;
                 }
             }