style: fix clippy warnings and improve code quality

Fix CI failures on Windows/macOS by addressing Rust 2024 edition requirements:

- io_uring.rs: Make HashMap import conditional for Linux only
  (HashMap is only used in Linux-specific IoUringContext struct)

- numa.rs: Add explicit unsafe blocks inside unsafe functions
  (Rust 2024 requires unsafe blocks for unsafe operations even
  inside unsafe fn, see rust-lang.org/edition-guide/rust-2024)

- aead/mod.rs, aead/session.rs: Fix import ordering per rustfmt

- integration_tests.rs: Prefix unused variable with underscore

All changes address -D warnings failures in CI runs #129-133.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: doublegate

crates/wraith-crypto/src/aead/mod.rs

@@ -37,6 +37,6 @@ pub mod replay;
 pub mod session;
 
 // Re-export all public types for backward compatibility
-pub use cipher::{AeadCipher, AeadKey, Nonce, Tag, KEY_SIZE, NONCE_SIZE, TAG_SIZE};
+pub use cipher::{AeadCipher, AeadKey, KEY_SIZE, NONCE_SIZE, Nonce, TAG_SIZE, Tag};
 pub use replay::ReplayProtection;
 pub use session::{BufferPool, SessionCrypto};

crates/wraith-crypto/src/aead/session.rs

@@ -3,9 +3,9 @@
 //! Provides bidirectional encrypted communication with automatic nonce
 //! management, replay protection, and key-committing AEAD.
 
-use crate::CryptoError;
 use super::cipher::{AeadKey, Nonce};
 use super::replay::ReplayProtection;
+use crate::CryptoError;
 use zeroize::ZeroizeOnDrop;
 
 /// Reusable buffer pool to avoid allocation in hot path.

crates/wraith-transport/src/io_uring.rs

@@ -45,6 +45,7 @@
 //! # }
 //! ```
 
+#[cfg(target_os = "linux")]
 use std::collections::HashMap;
 use std::io;
 use thiserror::Error;

crates/wraith-transport/src/numa.rs

@@ -156,7 +156,9 @@ pub unsafe fn allocate_on_node(size: usize, _node: usize) -> Option<*mut u8> {
     use std::alloc::{Layout, alloc};
 
     let layout = Layout::from_size_align(size, std::mem::align_of::<u8>()).ok()?;
-    let ptr = alloc(layout);
+    // SAFETY: Layout is valid (created from `from_size_align` which validated alignment).
+    // Caller is responsible for deallocating with `deallocate_on_node`.
+    let ptr = unsafe { alloc(layout) };
 
     if ptr.is_null() { None } else { Some(ptr) }
 }
@@ -194,8 +196,10 @@ pub unsafe fn deallocate_on_node(ptr: *mut u8, size: usize) {
     if !ptr.is_null() {
         // SAFETY: Layout matches the allocation from allocate_on_node (non-Linux path).
         // Pointer and size must be valid from original allocation (enforced by caller).
-        let layout = Layout::from_size_align_unchecked(size, std::mem::align_of::<u8>());
-        dealloc(ptr, layout);
+        // The alignment is always valid (1 for u8).
+        let layout = unsafe { Layout::from_size_align_unchecked(size, std::mem::align_of::<u8>()) };
+        // SAFETY: ptr was allocated with the same layout via allocate_on_node.
+        unsafe { dealloc(ptr, layout) };
     }
 }
 

tests/integration_tests.rs

@@ -948,7 +948,7 @@ fn test_relay_fallback() {
     use wraith_discovery::{ConnectionType, RelayInfo};
 
     // 1. Attempt direct connection (simulated failure)
-    let direct_connection = ConnectionType::Direct;
+    let _direct_connection = ConnectionType::Direct;
     let direct_available = false; // Simulate NAT/firewall blocking
 
     // 2. Fall back to relay