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/developer/01-core-foundation.md

@@ -8,7 +8,7 @@
 
 | # | System | Asset Type | Role |
 |---|--------|-----------|------|
-| 01 | `GI_GameTagRegistry` | Data Asset | Central GameplayTag namespace registry & validation |
+| 01 | `DA_GameTagRegistry` | Data Asset | Central GameplayTag namespace registry & validation |
 | 02 | `FL_GameUtilities` | Function Library | Static utility functions (safe casts, math, tags, debug) |
 | 03 | `I_InterfaceLibrary` | Interface Collection | All 9 framework interfaces for decoupled communication |
 | 04 | `GI_GameFramework` | Game Instance | Application kernel; owns subsystems, manages game phases |
@@ -42,7 +42,7 @@
 │    ├─► Bind to GI_GameFramework.OnGamePhaseChanged               │
 │    └─► Tick: accumulate ElapsedPlayTime when InGame              │
 │                                                                  │
-│  ALL SYSTEMS query GameplayTags via GI_GameTagRegistry            │
+│  ALL SYSTEMS query GameplayTags via DA_GameTagRegistry             │
 │  ALL SYSTEMS use FL_GameUtilities for safe casts & logging       │
 │  ALL SYSTEMS communicate via I_InterfaceLibrary interfaces       │
 │  ALL ITEMS are defined as DA_ItemData Data Assets                │
@@ -51,7 +51,7 @@
 
 ---
 
-## 01 — GI_GameTagRegistry: Central GameplayTag Registry
+## 01 — DA_GameTagRegistry: Central GameplayTag Registry
 
 **What It Does:** This is a **documentation anchor** Data Asset, not a runtime tag database. The actual GameplayTag definitions live in `DefaultGameplayTags.ini`, but this asset serves as the single place where all framework tag namespaces are documented and validated. Every system that uses GameplayTags references them from this registry's documented namespaces.
 
@@ -298,7 +298,7 @@ MainMenu → Loading → InGame ⇄ Paused
 **How It Works Internally:**
 
 **Core Properties (every item has these):**
-- `ItemTag` (GameplayTag) — unique identifier, must be registered in `GI_GameTagRegistry`
+- `ItemTag` (GameplayTag) — unique identifier, must be registered in `DA_GameTagRegistry`
 - `DisplayName`, `Description` (FText) — player-facing text
 - `Icon` (Texture2D soft reference) — UI icon
 - `WorldMesh` (StaticMesh soft reference) — 3D mesh when dropped in world
@@ -361,7 +361,7 @@ MainMenu → Loading → InGame ⇄ Paused
 
 13. DA_ItemData assets are loaded on demand ← Asset Manager async loads
 14. FL_GameUtilities calls available immediately ← Static library
-15. GI_GameTagRegistry.OnAssetLoaded() ← Fires when data asset loads
+15. DA_GameTagRegistry loaded by Asset Manager ← Fires when data asset loads (no native OnAssetLoaded in BP)
 ```
 
 ---
@@ -385,7 +385,7 @@ MainMenu → Loading → InGame ⇄ Paused
 | `GI_GameFramework` | GamePhase, session flags | Server sets; clients read via replicated dispatcher |
 | `GM_CoreGameMode` | Player spawning, chapter transitions, death routing | Server-only (extends replicated GameMode) |
 | `GS_CoreGameState` | Shared session state bus | **Fully replicated** — 5 vars with OnRep handlers |
-| `GI_GameTagRegistry` | Tag documentation | Read-only config — identical on all clients |
+| `DA_GameTagRegistry` | Tag documentation | Read-only config — identical on all clients |
 | `FL_GameUtilities` | Static utilities | No state — callable from any side |
 | `I_InterfaceLibrary` | Communication contracts | Interface calls work on any side; mutators must check authority |
 | `DA_ItemData` | Item definitions | Read-only Data Asset — identical on all clients |