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/Authoring/World/CycleDirectorAuthoring.cs

@@ -23,10 +23,10 @@ namespace ProjectM.Authoring
         public uint PostExpeditionDelayTicks = 300;
 
         [Tooltip("Siege size floor (Husk count) for a post-expedition retaliation.")]
-        public int SiegeSizeBase = 5;
+        [Min(0)] public int SiegeSizeBase = 5;
 
         [Tooltip("Extra Husks per unit of resources hauled back this run (0 = flat SiegeSizeBase).")]
-        public int SiegeSizePerResource = 0;
+        [Min(0)] public int SiegeSizePerResource = 0;
 
         [Tooltip("Max server ticks a siege may run before it auto-collapses (no soft-lock). 0 = no cap.")]
         public uint SiegeTimeoutTicks = 3600;
@@ -38,11 +38,11 @@ namespace ProjectM.Authoring
         public uint ScheduleIntervalTicks = 2700;
 
         [Tooltip("Extra Husks per surviving wave (siege size = SiegeSizeBase + this * WaveNumber). 0 = flat.")]
-        public int ScheduleSizePerWave = 1;
+        [Min(0)] public int ScheduleSizePerWave = 1;
 
         [Header("Endgame — Engine Core (END-1)")]
         [Tooltip("Baked integrity ceiling of the losable Engine Core. Current is born full (or the persisted wounded value on Continue).")]
-        public int CoreIntegrityMax = 100;
+        [Min(1)] public int CoreIntegrityMax = 100;