feat: Implement BPC_PlatformServiceAbstraction for unified platform detection and SDK routing

- Added BPC_PlatformServiceAbstraction to centralize platform detection and SDK routing for achievements, cloud saves, and overlays.
- Updated dependencies across various systems to utilize the new platform service for consistent platform handling.
- Deprecated old platform enums in favor of a unified EPlatformFamily enum.
- Enhanced documentation for affected systems to reflect changes in platform handling and dependencies.

docs/checklists/cpp-blueprint-status.md

@@ -183,6 +183,7 @@ Abbreviations:
 | 102-114 | All 13 systems | 🔵 | ✅ | BP children + widget BPs |
 | 148 | `BPC_HapticsController` | 🔵 (Blueprint-only) | ✅ | ⬜ BP child attach to PlayerController |
 | 149 | `BPC_RenderPipelineManager` | 🔵 (Blueprint-only) | ✅ | ⬜ BP child attach to PlayerController |
+| 150 | `BPC_PlatformServiceAbstraction` | 🔵 (Blueprint-only) | ✅ | ⬜ BP child attach to GI_GameFramework |
 
 ### Data Assets (14-data-assets — 16 systems)
 

docs/checklists/remaining-blueprint-build-order.md

@@ -726,6 +726,7 @@ All 16 are Data Asset definitions. No code — create Data Asset instances per c
 | 105 | `SS_SettingsSystem` | BP child of GameInstanceSubsystem | Settings persistence: save/load config to disk, apply on boot |
 | 148 | `BPC_HapticsController` | BP child of ActorComponent | Haptics: GameplayTag-driven force feedback, DualSense triggers, heartbeat pulse |
 | 149 | `BPC_RenderPipelineManager` | BP child of ActorComponent | Render pipeline: quality presets, GI/shadows/upscaling per platform, PlanarCapture aware |
+| 150 | `BPC_PlatformServiceAbstraction` | BP child of ActorComponent | Central platform authority: detection, SDK routing (Steam/PSN/Xbox/Nintendo), input/GFX/achievement coordination |
 
 ---