Update dependencies and refactor random number generation

- Bump versions of several dependencies in Cargo.toml for improved functionality and security, including:
  - socket2 to 0.6
  - nix to 0.31
  - toml to 1.0
  - x509-parser to 0.18
  - dashmap to 6.1
  - rand to 0.10
  - reqwest to 0.13
  - notify to 8.2
  - ipnetwork to 0.21
  - webpki-roots to 1.0
  - criterion to 0.8
- Introduce `OnceLock` for secure random number generation in multiple modules to ensure thread safety and reduce overhead.
- Refactor random number generation calls to use the new `RngExt` trait methods for consistency and clarity.
- Add new PNG files for architectural documentation.

src/network/stun.rs

@@ -2,13 +2,20 @@
 #![allow(dead_code)]
 
 use std::net::{IpAddr, Ipv4Addr, Ipv6Addr, SocketAddr};
+use std::sync::OnceLock;
 
 use tokio::net::{lookup_host, UdpSocket};
 use tokio::time::{timeout, Duration, sleep};
 
+use crate::crypto::SecureRandom;
 use crate::error::{ProxyError, Result};
 use crate::network::dns_overrides::{resolve, split_host_port};
 
+fn stun_rng() -> &'static SecureRandom {
+    static STUN_RNG: OnceLock<SecureRandom> = OnceLock::new();
+    STUN_RNG.get_or_init(SecureRandom::new)
+}
+
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub enum IpFamily {
     V4,
@@ -49,8 +56,6 @@ pub async fn stun_probe_family_with_bind(
     family: IpFamily,
     bind_ip: Option<IpAddr>,
 ) -> Result<Option<StunProbeResult>> {
-    use rand::RngCore;
-
     let bind_addr = match (family, bind_ip) {
         (IpFamily::V4, Some(IpAddr::V4(ip))) => SocketAddr::new(IpAddr::V4(ip), 0),
         (IpFamily::V6, Some(IpAddr::V6(ip))) => SocketAddr::new(IpAddr::V6(ip), 0),
@@ -88,7 +93,7 @@ pub async fn stun_probe_family_with_bind(
     req[0..2].copy_from_slice(&0x0001u16.to_be_bytes()); // Binding Request
     req[2..4].copy_from_slice(&0u16.to_be_bytes()); // length
     req[4..8].copy_from_slice(&0x2112A442u32.to_be_bytes()); // magic cookie
-    rand::rng().fill_bytes(&mut req[8..20]); // transaction ID
+    stun_rng().fill(&mut req[8..20]); // transaction ID
 
     let mut buf = [0u8; 256];
     let mut attempt = 0;