Inventory: per-player items backbone (DR-026 Phase 0)

Data-driven ItemDatabase catalog + per-player replicated InventorySlot ([GhostField] OwnerSendType.All, a StatModifier twin). Harvest reroutes to the firing player's personal inventory (optional ComponentLookup<GhostOwner> in ResourceHarvestSystem; remainder/un-owned -> ledger); the G-key InventoryDepositRequest RPC moves the bag into the shared ledger the build economy spends. Catalog asset (Aether/Ore/Biomass + Stone Pickaxe) wired into the Gameplay subscene; read-only HUD inventory panel. ushort ItemId subsumes ResourceId; byte Category/Tier baked for gear-tier progression. Session-only (no SaveData bump).

Play-validated host+client: catalog baked into both worlds, the re-baked player ghost carries InventorySlot with a clean handshake, a server write replicates to the client owner, the deposit RPC round-trips, and the HUD renders catalog names. See DR-026.

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

Assets/_Project/Scripts/Simulation/Items/InventoryDepositRequest.cs

@@ -0,0 +1,23 @@
+using Unity.NetCode;
+
+namespace ProjectM.Simulation
+{
+    /// <summary>
+    /// Client -&gt; server request to move items from the sender's PERSONAL inventory into the shared base
+    /// stockpile (the global <see cref="ResourceLedger"/> the build/upgrade/automation economy spends from).
+    /// A one-off action, so it is an RPC (not a per-tick predicted input), and the server applies it exactly
+    /// once in the plain SimulationSystemGroup (no rollback double-apply). Payload is plain blittable scalars
+    /// (no entity refs, no enum): the server resolves the sender's player from the RPC's SourceConnection. The
+    /// wire type is UNCONDITIONAL (never #if-gated) so the RpcCollection hash matches across release/dev peers;
+    /// only the send/receive SYSTEMS may be #if-gated.
+    /// </summary>
+    public struct InventoryDepositRequest : IRpcCommand
+    {
+        /// <summary>Item to deposit, or 0 to deposit EVERYTHING the player is carrying. The server branches on
+        /// 0 BEFORE any per-item withdraw and never writes a 0-id row.</summary>
+        public ushort ItemId;
+
+        /// <summary>Quantity to deposit; &lt;= 0 means "all of that item" (ignored when ItemId is 0).</summary>
+        public int Count;
+    }
+}