Hygiene B3: single-sourcing & magic-number consolidation

- StructureCatalogAuthoring: WallCostOre -> WallCostBiomass (it bakes a Biomass cost; [FormerlySerializedAs] preserves the scene value).
- Harvester/Fabricator authoring: resource-id byte defaults reference ResourceId.Ore/.Charge instead of magic 2/4.
- RegionMath.RegionBoundaryX (= ExpeditionOffsetX*0.5) single-sources the region-flip X used by HudSystem + OnboardingSystem (was 500f in 3 places).
- CharacterComponent.DefaultGroundedSharpness single-sources the CC sharpness 15f (GetDefault, DashSystem, PlayerDeathStateSystem, PlayerCharacterAuthoring).
- InventorySlot [InternalBufferCapacity] references Tuning.InventoryMaxSlots.
- ConnectionMode enum -> byte-const class (project convention; removes the latent enum-in-Burst trap); field + one Seed() param become byte.
- Tuning.ChargerWindupTicks single-sources the Charger telegraph windup (EnemyBaker + TuningConfig.Defaults; was a bare 30 that could drift).
- (TicksPerSecond deliberately NOT added: no seconds->ticks conversion site exists; the tick-count fields are per-authoring designer tunables, so a const would be unreferenced.)

451/451 EditMode tests pass.

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

Assets/_Project/Scripts/Simulation/Player/CharacterComponents.cs

@@ -16,6 +16,10 @@ namespace ProjectM.Simulation
     [Serializable]
     public struct CharacterComponent : IComponentData
     {
+        /// <summary>The CC's default grounded-movement smoothing sharpness — the single source for GetDefault, the
+        /// authoring default, DashSystem's base, and the death-state reset.</summary>
+        public const float DefaultGroundedSharpness = 15f;
+
         /// <summary>How quickly RelativeVelocity is lerped toward the target velocity on the ground.</summary>
         public float GroundedMovementSharpness;
 
@@ -26,7 +30,7 @@ namespace ProjectM.Simulation
         {
             return new CharacterComponent
             {
-                GroundedMovementSharpness = 15f,
+                GroundedMovementSharpness = DefaultGroundedSharpness,
                 StepAndSlopeHandling = BasicStepAndSlopeHandlingParameters.GetDefault(),
             };
         }