feat: Enhance interaction and inventory systems with new components and functionality

- Added BPC_UsableWorldObjectSystem for handling various interactable world objects with detailed manual implementation guide.
- Introduced BPC_ActiveItemSystem to manage quick slots and active item usage, including cycling and selection logic.
- Implemented BPC_DocumentArchiveSystem for managing collectible documents with read tracking and categorization.
- Developed BPC_JournalSystem for narrative entries with auto-adding features based on gameplay events.
- Created BPC_KeyItemSystem for key management with consumable and persistent key support.
- Enhanced BPC_FirearmSystem for ranged weapon mechanics, including hitscan and projectile firing.
- Updated BPC_MeleeSystem for melee combat with combo and blocking mechanics.
- Established BPC_ReloadSystem for managing weapon reloading processes, including partial reloads and state management.

docs/blueprints/08-weapons/78_BPC_ReloadSystem.md

@@ -59,4 +59,106 @@
 
 - ReloadMontage from DA_WeaponData per weapon; swap for each weapon type
 - Partial reload enabled per weapon (e.g. shotguns use individual shell reloads)
-- AmmoTypeTag links to correct ammo pool in BPC_AmmoResourceSystem
+- AmmoTypeTag links to correct ammo pool in BPC_AmmoResourceSystem
+
+---
+
+## Manual Implementation Guide
+
+### Class Setup
+1. Create Blueprint Class: Parent = `ActorComponent`, Name = `BPC_ReloadSystem`
+2. Attach to `BP_WeaponBase` or `BPC_FirearmSystem`
+3. Weapon must have a `ReloadMontage` with Animation Notifies
+
+### Variable Init (BeginPlay)
+```
+Event BeginPlay
+  ├─ Set bIsReloading = false
+  ├─ Set bPartialReload = false
+  ├─ Get Owner → Read DA_WeaponData → Load ReloadMontage, AmmoTypeTag, MagazineSize
+  └─ Cache: BPC_AmmoComponent, BP_WeaponBase (for state check)
+```
+
+### Function Implementations
+
+#### `RequestReload()` → `void`
+
+```
+[Function: RequestReload]
+  Step 1: Get BP_WeaponBase → Check WeaponState == Ready → If not, return (can't reload while firing)
+  Step 2: Call CanReload() → Branch:
+    False → Fire OnReloadFailed → Return
+    True → Call BeginReload()
+```
+
+#### `CanReload()` → `Boolean`
+
+```
+[Function: CanReload] (Pure)
+  Step 1: Get BPC_AmmoComponent → Call GetAmmoInMagazine()
+    If magazine >= MagazineSize → Return false (already full)
+  Step 2: Get BPC_AmmoComponent → Call GetReserveAmmo(AmmoTypeTag)
+    If reserve <= 0 → Return false (no ammo to load)
+  Step 3: Return true
+```
+
+#### `BeginReload()` → `void`
+
+```
+[Function: BeginReload]
+  Step 1: Set bIsReloading = true
+  Step 2: Notify BP_WeaponBase → SetWeaponState(Reloading)
+  Step 3: Play Montage (ReloadMontage)
+  Step 4: Fire OnReloadStarted
+
+  Step 5: Animation Notify "TransferRounds" setup:
+    In the animation montage, add Notify at the frame where the magazine is inserted.
+    On trigger → Call CompleteReload()
+
+  Step 6: Animation Notify "ReloadEnd" setup:
+    Add Notify at montage end → Call FinishReload()
+```
+
+#### `CompleteReload()` → `void` *(Called by Notify "TransferRounds")*
+
+```
+[Function: CompleteReload]
+  Step 1: Get BPC_AmmoComponent:
+    MagazineCurrent = GetAmmoInMagazine()
+    ReserveCurrent = GetReserveAmmo(AmmoTypeTag)
+  Step 2: RoundsToAdd = Min(MagazineSize - MagazineCurrent, ReserveCurrent)
+  Step 3: BPC_AmmoComponent.RemoveReserveAmmo(AmmoTypeTag, RoundsToAdd)
+  Step 4: BPC_AmmoComponent.AddMagazineAmmo(RoundsToAdd)
+```
+
+#### `FinishReload()` → `void` *(Called by Notify "ReloadEnd")*
+
+```
+  Step 1: Set bIsReloading = false
+  Step 2: Notify BP_WeaponBase → SetWeaponState(Ready)
+  Step 3: Fire OnReloadCompleted(RoundsToAdd)
+```
+
+#### `InterruptReload()` → `void`
+
+```
+[Function: InterruptReload]
+  Step 1: Branch on bIsReloading → If false, return
+  Step 2: If bPartialReload AND CompleteReload already called:
+    Keep transferred rounds (partial reload success)
+  Step 3: Else: no rounds transferred
+  Step 4: Stop Montage (ReloadMontage)
+  Step 5: Set bIsReloading = false
+  Step 6: Notify BP_WeaponBase → SetWeaponState(Ready)
+  Step 7: Fire OnReloadInterrupted(RoundsTransferred)
+```
+
+### Build Checklist
+- [ ] Create BPC_ReloadSystem, add to BP_RangedWeapon
+- [ ] Create ReloadMontage per weapon with Notifies: TransferRounds, ReloadEnd
+- [ ] Implement CanReload checking magazine fullness and reserve ammo
+- [ ] Implement BeginReload with montage playback and state lock
+- [ ] Wire CompleteReload to ammo transfer
+- [ ] Wire FinishReload to state restoration
+- [ ] Implement InterruptReload for mid-reload weapon swap
+- [ ] Test: empty magazine → reload → rounds transfer → magazine full