Initial commit: split VNOX monorepo into VNOX-Client

Desktop client with egui + wgpu UI, audio pipeline (cpal/opus/rodio),
networking (LNEx protocol), and identity management with encrypted vault.

Jitter buffer module extracted from voice-node for standalone operation.

src/ui/state/models.rs

@@ -0,0 +1,92 @@
+use std::collections::HashMap;
+
+#[derive(Debug, Clone, PartialEq, Default)]
+pub enum SettingsPage {
+    Identity,
+    #[default]
+    Voice,
+    AudioOutput,
+    Network,
+    Overlay,
+    Appearance,
+    Keybinds,
+    Plugins,
+    Advanced,
+}
+
+#[derive(Debug, Clone)]
+pub struct Channel {
+    pub id: String,
+    pub name: String,
+    pub kind: String,
+    pub members: Vec<String>,
+}
+
+#[derive(Debug, Clone)]
+pub struct ChatMessage {
+    pub message_id: String,
+    pub sender_id: String,
+    pub content: String,
+    pub timestamp: i64,
+    pub edited: bool,
+    pub reactions: HashMap<String, Vec<String>>,
+    /// Optional message_id this message is replying to.
+    #[cfg_attr(not(test), allow(dead_code))]
+    pub reply_to: Option<String>,
+}
+
+#[derive(Debug, Clone)]
+pub struct DmConversation {
+    pub dm_id: String,
+    pub other_user_id: String,
+    pub other_nickname: String,
+    pub unread_count: u32,
+}
+
+#[derive(Debug, Clone)]
+pub struct GuildState {
+    pub guild_id: String,
+    pub name: String,
+    pub owner_id: String,
+    pub member_count: u32,
+}
+
+#[derive(Debug, Clone)]
+pub struct FriendState {
+    pub user_id: String,
+    pub nickname: String,
+    pub status: String,
+    pub since: i64,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct NodeBookmark {
+    pub label: String,
+    pub address: String,
+}
+
+pub(crate) fn default_bookmarks() -> Vec<NodeBookmark> {
+    Vec::new()
+}
+
+pub(crate) fn bookmark_label_from_address(address: &str) -> String {
+    address
+        .split(':')
+        .next()
+        .filter(|s| !s.is_empty())
+        .unwrap_or(address)
+        .chars()
+        .take(12)
+        .collect()
+}
+
+pub(crate) fn now_utc_hms() -> String {
+    let secs = std::time::SystemTime::now()
+        .duration_since(std::time::UNIX_EPOCH)
+        .map(|d| d.as_secs())
+        .unwrap_or(0);
+    let h = (secs % 86400) / 3600;
+    let m = (secs % 3600) / 60;
+    let s = secs % 60;
+    format!("{h:02}:{m:02}:{s:02}")
+}