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>

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