feat: Add multiplayer networking architecture and documentation updates

- Updated Master Blueprint Index to include Multiplayer Networking support.
- Added detailed Multiplayer Networking sections across all developer documentation (01-11).
- Introduced authority maps, key patterns, and RPC guidelines for each system.
- Established a comprehensive multiplayer networking architecture document outlining core principles, replication strategies, and anti-cheat considerations.
- Enhanced UI documentation to clarify local-only behavior and binding to replicated dispatchers.
- Implemented client prediction strategies and RPC naming conventions for consistency across the framework.

docs/blueprints/02-player/14_BPC_CameraStateLayer.md

@@ -326,4 +326,22 @@ flowchart TD
 
 ---
 
+## 11. Multiplayer Networking
+
+**Replication: State only — effects are local.** Camera FOV blending, shake, and post-processing are per-client experiences. Only the state enum syncs.
+
+| Variable | Condition | Purpose |
+|----------|-----------|---------|
+| `CurrentCameraState` | `Replicated` | Synced for shared context (e.g., all players know someone is aiming) |
+
+### Authority
+- `RequestCameraState` can be called by client; state replicates to all.
+- `PlayCameraShake`, `ApplyPostProcessOverride`, `BlendToTargetFOV` are **local only**.
+- FOV pulse, head bob, camera offset blending are **local only**.
+
+### Client Prediction
+- Camera is inherently local — no prediction needed. State changes replicate for other players' awareness.
+
+---
+
 *Blueprint Spec: Camera State Layer. Conforms to TEMPLATE.md v1.0 — part of the UE5 Modular Game Framework.*