Equipment: weapon-granted abilities + gear mods (DR-027 Phase 1)

Equipment slots reusing the AbilityRef/StatModifier machinery: EquipmentSlot [GhostField] buffer (index=slot), server-only event-driven EquipSystem (RPC). Weapon -> AbilityRef.Id swaps the attack (prefab + base stats, prediction-correct); gear -> StatModifiers tagged a reserved per-slot EquipSourceId, stripped target-agnostically via RemoveBySourceId. Item mods are INLINE on ItemDefBlob (a nested BlobArray reads empty under the by-value TryGetItem copy). Atomic equip-over swap (no item loss); DefaultAbility restores the unarmed ability on weapon-unequip. Client keys + build-safe hooks; HUD equipment panel + click-to-equip. 4 catalog weapon/gear items wired + re-baked.

Play-validated host+client: weapon equip swaps AbilityRef on both worlds, gear folds into EffectiveCharacterStats, unequip reverses + restores DefaultAbility, all replicated to the owner. See DR-027.

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

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

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+using Unity.Entities;
+using Unity.NetCode;
+
+namespace ProjectM.Simulation
+{
+    /// <summary>
+    /// One equipment slot on the player. The per-player buffer holds exactly <see cref="EquipSlotId.Count"/>
+    /// rows in fixed slot order (the buffer INDEX is the slot — Weapon=0/Armor=1/Trinket=2/Tool=3), so only the
+    /// equipped item id needs to replicate; there is no separate Slot field to desync. A [GhostField]
+    /// <see cref="SendToOwnerType.All"/> buffer (a <see cref="StatModifier"/>/<see cref="InventorySlot"/> twin)
+    /// so the owning client's HUD can show its loadout; the server is the SOLE writer (EquipSystem).
+    ///
+    /// The actual effects — AbilityRef.Id from the Weapon slot + StatModifiers per slot — are applied
+    /// EVENT-DRIVEN by EquipSystem (once per equip/unequip), NOT re-derived from this buffer each tick; this
+    /// buffer is the replicated record of WHAT is equipped (HUD-facing + persistence-ready), not the effect.
+    /// NOTE: adding this [GhostField] buffer changes the player ghost serialization hash → the player
+    /// prefab/subscene MUST be re-baked consistently in both worlds (see <see cref="InventorySlot"/>).
+    /// </summary>
+    [GhostComponent(OwnerSendType = SendToOwnerType.All)]
+    [InternalBufferCapacity(4)]
+    public struct EquipmentSlot : IBufferElementData
+    {
+        /// <summary>Item equipped in this slot (0 = empty). The buffer INDEX is the <see cref="EquipSlotId"/>.</summary>
+        [GhostField] public ushort ItemId;
+    }
+}