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/transport/middle_proxy/pool_writer.rs

@@ -6,7 +6,7 @@ use std::io::ErrorKind;
 
 use bytes::Bytes;
 use bytes::BytesMut;
-use rand::Rng;
+use rand::RngExt;
 use tokio::sync::mpsc;
 use tokio_util::sync::CancellationToken;
 use tracing::{debug, info, warn};