Hygiene B4d: PlayerResolve dedup + explicit Temp-ECB Dispose tail

- New Server/PlayerResolve.TryResolve single-sources the RPC
  SourceConnection -> NetworkId -> conn->player map resolve (3 sites:
  ClassSelectReceive, PrepPurchase, DebugCommandReceive); EntityManager
  reads keep it source-gen-safe from Bursted receivers.
- ecb.Dispose() after Playback in 9 Temp-ECB systems (explicit-lifetime
  hygiene).
- The TuningConfig.GetOrDefault(ref state) variant of this tail was
  REVERTED: state.GetEntityQuery in OnUpdate trips the Entities
  "creates a query during OnUpdate" diagnostic per system per world
  (caught in Play smoke) - the SystemAPI.TryGetSingleton idiom is
  already source-gen-optimal, confirming the original B4 deferral.

Verified: 466/466 EditMode green on the final tree, console clean,
Play smoke 0 errors.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Assets/_Project/Scripts/Server/PlayerResolve.cs

@@ -0,0 +1,27 @@
+using Unity.Collections;
+using Unity.Entities;
+using Unity.NetCode;
+
+namespace ProjectM.Server
+{
+    /// <summary>
+    /// Shared server-side RPC sender resolution: a request's <c>ReceiveRpcCommandRequest.SourceConnection</c> →
+    /// its <see cref="NetworkId"/> → the conn→player map that every RPC-receive system builds (the
+    /// AbilityUpgradeSystem / ReadyToggle idiom). The MAP BUILD stays per-caller — each system's player query
+    /// carries different extra required components (InventorySlot / EquipmentSlot / StatModifier / BoonOffer /
+    /// PlayerReady / …) — but the RESOLVE step is byte-for-byte identical across sites, so it lives here once.
+    /// Burst-safe (plain <see cref="EntityManager"/> reads; called from <c>[BurstCompile]</c> receivers).
+    /// </summary>
+    public static class PlayerResolve
+    {
+        /// <summary>True (with <paramref name="player"/> set) iff <paramref name="conn"/> has a
+        /// <see cref="NetworkId"/> present in <paramref name="map"/>. Behaviour-identical to the inline
+        /// <c>HasComponent&lt;NetworkId&gt;(conn) &amp;&amp; map.TryGetValue(GetComponent&lt;NetworkId&gt;(conn).Value, out player)</c>.</summary>
+        public static bool TryResolve(ref SystemState state, NativeHashMap<int, Entity> map, Entity conn, out Entity player)
+        {
+            player = Entity.Null;
+            return state.EntityManager.HasComponent<NetworkId>(conn)
+                && map.TryGetValue(state.EntityManager.GetComponentData<NetworkId>(conn).Value, out player);
+        }
+    }
+}