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/handler/guild/list.rs

@@ -0,0 +1,61 @@
+use anyhow::Result;
+use tokio::net::TcpStream;
+
+use crate::{
+    domain::session,
+    net::{io, state::State},
+    proto::{GuildInfo, GuildListPayload, PacketId, SessionCrypto, to_payload},
+};
+
+pub async fn handle_guild_list(
+    stream: &mut TcpStream,
+    seq: &mut u32,
+    session_id: &str,
+    crypto: &SessionCrypto,
+    state: &State,
+) -> Result<()> {
+    let sess = session::get(&state.sessions, session_id)
+        .await
+        .ok_or_else(|| anyhow::anyhow!("session not found"))?;
+
+    let rows = state.storage.list_user_guilds(&sess.user_id).await?;
+    let guilds: Vec<GuildInfo> = rows
+        .iter()
+        .map(|g| GuildInfo {
+            id: g.id.clone(),
+            owner_id: g.owner_id.clone(),
+            name: g.name.clone(),
+            member_count: g.member_count,
+            created_at: g.created_at,
+        })
+        .collect();
+
+    for g in &rows {
+        let roles = state.storage.get_user_roles(&g.id, &sess.user_id).await?;
+        let color = roles
+            .iter()
+            .max_by_key(|r| r.position)
+            .map(|r| r.color.clone())
+            .unwrap_or_else(|| "#ffffff".into());
+        io::send_encrypted(
+            stream,
+            PacketId::UserRoleUpdate,
+            seq,
+            &to_payload(
+                &serde_json::json!({"user_id": sess.user_id, "guild_id": g.id, "color": color}),
+            ),
+            crypto,
+        )
+        .await?;
+    }
+
+    io::send_encrypted(
+        stream,
+        PacketId::GuildList,
+        seq,
+        &to_payload(&GuildListPayload { guilds }),
+        crypto,
+    )
+    .await?;
+    Ok(())
+}