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/Connection/ConnectionConfig.cs

@@ -11,17 +11,19 @@ namespace ProjectM.Simulation
     /// <c>NetworkStreamRequestConnect</c> and clears <see cref="Requested"/>. Direct IP/LAN only for now —
     /// Unity Relay is deferred to a later pass. Created per-world as a singleton.
     /// </summary>
-    public enum ConnectionMode : byte
+    /// <summary>Connection intent values (byte-const, matching the project's op/id convention — not an enum, so
+    /// they stay safe if a consumer is ever [BurstCompile]d). Written to <see cref="ConnectionConfig.Mode"/>.</summary>
+    public static class ConnectionMode
     {
-        None,
-        Host,
-        Join,
+        public const byte None = 0;
+        public const byte Host = 1;
+        public const byte Join = 2;
     }
 
     public struct ConnectionConfig : IComponentData
     {
         /// <summary>What to do with this world's network stream.</summary>
-        public ConnectionMode Mode;
+        public byte Mode;
 
         /// <summary>Dotted IPv4 to connect to (Join). Ignored for Host (binds AnyIpv4).</summary>
         public FixedString64Bytes Address;