Update documentation for player, inventory, and weapon systems

- Added C++ status updates for player systems (02-player-systems.md) indicating the implementation status of systems 08-11 and their relation to BPC_StateManager.
- Enhanced inventory systems documentation (04-inventory-systems.md) with C++ status for BPC_InventorySystem and DA_ItemData, clarifying their implementation details.
- Updated weapons systems documentation (08-weapons-systems.md) to reflect the C++ implementation status of BPC_DamageReceptionSystem and stubs for hit reaction and shield defense systems.

docs/developer/02-player-systems.md

@@ -2,6 +2,8 @@
 
 **Category Purpose:** These 8 systems form the player character's core simulation layer — health, stamina, stress, movement, hiding, first-person body, camera, and metrics tracking. They cascade: health affects stress, stress affects movement, movement affects camera. All feed into the animation system (ABP_GASP) via event dispatchers.
 
+**C++ Status:** Systems 08-11 have C++ stubs (`Source/PG_Framework/Public/Player/`) providing UCLASS definition, basic variables, and event dispatchers. The Blueprint child provides the full runtime implementation. Systems 12-15 are BP-only. All 8 are referenced by `BPC_StateManager` (130) for gating evaluations.
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 ## System Index

docs/developer/04-inventory-systems.md

@@ -2,6 +2,8 @@
 
 **Category Purpose:** These 11 systems form the complete inventory management layer — core item storage grid, world containers, item pickups, consumable usage, equipment slots, item combination/crafting, key item tracking, document archiving, quick slots, journal tracking, and collectible progression. The `BPC_InventorySystem` is the single source of truth for all item data; every other inventory subsystem reads from and writes through it.
 
+**C++ Status:** System 31 (`BPC_InventorySystem`) is a full C++ implementation (`Source/PG_Framework/Public/Inventory/BPC_InventorySystem.h`) with native-speed TArray operations, auto-stacking, and weight tracking. System 07 (`DA_ItemData`) is also full C++. System 120 (`DA_EquipmentConfig`) is a C++ stub. All other inventory systems are BP-only.
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 ## System Index

docs/developer/08-weapons-systems.md

@@ -2,6 +2,8 @@
 
 **Category Purpose:** These 11 systems form the complete combat layer — weapon actors (ranged and melee), ammo management, combat feedback (hit markers, kill confirm), damage reception and resistance, death cause tracking, firearm specialization, hit reactions, melee combat, recoil patterns, reload mechanics, and shield defense. The `BP_WeaponBase` is the base actor class extended by all weapons; combat flows through `BPC_DamageReceptionSystem` to `BPC_HealthSystem`.
 
+**C++ Status:** System 72 (`BPC_DamageReceptionSystem`) is a full C++ implementation — attach the component directly. Systems 75 (`BPC_HitReactionSystem`) and 79 (`BPC_ShieldDefenseSystem`) are C++ stubs with basic variables and dispatchers — create BP children for full logic. Systems 69-71, 73-74, 76-78 are BP-only.
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 ## System Index