chore: fix all clippy warnings across workspace

crates/quicproquo-client/tests/e2e.rs

@@ -1,5 +1,7 @@
 // cargo_bin! only works for current package's binary; we spawn qpq-server from another package.
 #![allow(deprecated)]
+#![allow(clippy::unwrap_used)]
+#![allow(clippy::await_holding_lock)] // AUTH_LOCK intentionally held across await to serialize tests
 
 use std::{path::PathBuf, process::Command, sync::Mutex, time::Duration};
 
@@ -8,7 +10,6 @@ use portpicker::pick_unused_port;
 use rand::RngCore;
 use tempfile::TempDir;
 use tokio::time::sleep;
-use hex;
 
 // Required by rustls 0.23 when QUIC/TLS is used from this process (e.g. client in test).
 fn ensure_rustls_provider() {
@@ -46,7 +47,7 @@ impl Drop for ChildGuard {
     }
 }
 
-async fn wait_for_health(server: &str, ca_cert: &PathBuf, server_name: &str) -> anyhow::Result<()> {
+async fn wait_for_health(server: &str, ca_cert: &std::path::Path, server_name: &str) -> anyhow::Result<()> {
     let local = tokio::task::LocalSet::new();
     for _ in 0..30 {
         if local
@@ -1090,7 +1091,7 @@ async fn e2e_key_rotation_update_path() -> anyhow::Result<()> {
 
     let alice_seed = bincode::deserialize::<StoredStateCompat>(&std::fs::read(&alice_state)?)?.identity_seed;
     let bob_seed = bincode::deserialize::<StoredStateCompat>(&std::fs::read(&bob_state)?)?.identity_seed;
-    let alice_pk = IdentityKeypair::from_seed(alice_seed).public_key_bytes().to_vec();
+    let _alice_pk = IdentityKeypair::from_seed(alice_seed).public_key_bytes().to_vec();
     let bob_pk = IdentityKeypair::from_seed(bob_seed).public_key_bytes().to_vec();
     let bob_pk_hex = hex_encode(&bob_pk);
 
@@ -1372,7 +1373,7 @@ async fn e2e_file_upload_download() -> anyhow::Result<()> {
 
     // Build 2 KB of known data.
     let pattern = b"hello-world-file-test\n";
-    let repeat_count = (2048 + pattern.len() - 1) / pattern.len();
+    let repeat_count = 2048_usize.div_ceil(pattern.len());
     let file_data: Vec<u8> = pattern.iter().copied().cycle().take(repeat_count * pattern.len()).collect();
     let file_data = &file_data[..2048]; // exactly 2 KB
 
@@ -1472,7 +1473,7 @@ async fn e2e_file_upload_download() -> anyhow::Result<()> {
         .await?;
 
     anyhow::ensure!(
-        partial == &file_data[100..300],
+        partial == file_data[100..300],
         "partial download [100..300] does not match expected slice"
     );