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/Items/InventorySlot.cs

@@ -23,7 +23,7 @@ namespace ProjectM.Simulation
     /// subscene MUST be re-baked (consistently in both worlds) or the connect handshake desyncs.
     /// </summary>
     [GhostComponent(OwnerSendType = SendToOwnerType.All)]
-    [InternalBufferCapacity(24)]
+    [InternalBufferCapacity(Tuning.InventoryMaxSlots)]
     public struct InventorySlot : IBufferElementData
     {
         /// <summary>Item carried in this slot (0 = empty/unused; aligns with InventoryMath's 0-id no-op).</summary>