Initial commit: split VNOX monorepo into VNOX-Server

Unified server binary (vnox-serverd) combining:
- Gateway (TCP, auth, channels, sessions, SQLite)
- Voice-node (UDP relay, Opus, jitter buffer)

Standalone gateway (vnox-gateway) and voice-node (vnox-voice-node) preserved as sub-crates.

gateway/src/proto/payloads/mod.rs

@@ -0,0 +1,7 @@
+mod channel;
+mod guild;
+mod social;
+
+pub use channel::*;
+pub use guild::*;
+pub use social::*;