Refactor GameplayTag documentation and implementation

- Updated references from GI_GameTagRegistry to DA_GameTagRegistry in architecture overview and implementation patterns documentation.
- Added new Blueprint specification for GI_StarterGameInstance, detailing its purpose, configuration, and integration pattern.
- Introduced DA_GameTagRegistry Blueprint specification, centralizing GameplayTag management and providing functions for tag validation and logging.
- Created documentation for the Starter GameInstance, outlining its role in the project setup and how other systems can integrate with it.

docs/architecture/blueprint-limitations-workarounds.md

@@ -12,7 +12,7 @@ This document catalogs all UE5 engine functions that are C++ only (not exposed t
 
 **Engine Function:** `UGameplayTagsManager::Get().RequestAllGameplayTags()`  
 **UE5 Node:** Does NOT exist in Blueprint  
-**Files Affected:** `01_GI_GameTagRegistry.md`, any system that needs to enumerate all tags
+**Files Affected:** `01_DA_GameTagRegistry.md`, any system that needs to enumerate all tags
 
 **Blueprint Workaround — Data Table Proxy (Multi-Table):**
 
@@ -72,7 +72,7 @@ OR create a Blueprint Macro Library with a macro that wraps the subsystem lookup
 ### 3.1 `OnAssetLoaded` / `BeginPlay` on Data Assets (Not Available)
 
 **Engine Behavior:** `UPrimaryDataAsset` does not have `BeginPlay`, `Tick`, or event graphs. It's a pure data container.  
-**Files Affected:** `01_GI_GameTagRegistry.md`, all DA_* specs
+**Files Affected:** `01_DA_GameTagRegistry.md`, all DA_* specs
 
 **Blueprint Workaround:** Move initialization and validation logic to an owning system: