fix: resolve all fmt and clippy warnings

Main lib (src/):
- Add #[allow(dead_code)] for build_info field (stored to prevent Prometheus unregistration)
- Add #[allow(dead_code)] for first_seen field (reserved for future rate limiting)
- Replace .or_insert_with(RelaySyncNeeds::default) with .or_default()
- Replace manual div_ceil implementations with .div_ceil(100)

Test code (tests/):
- Replace .expect(&format!(...)) with .unwrap_or_else(|_| panic!(...))
- Remove needless borrows in fetch_metrics() calls
- Add #[allow(dead_code)] and #[allow(unused_imports)] to test helpers module

grasp-audit:
- Apply cargo fmt to fix formatting

1 files changed, 3 insertions, 3 deletions

diff --git a/tests/sync/metrics.rs b/tests/sync/metrics.rs
index 26d379d..14e1dfd 100644
--- a/tests/sync/metrics.rs
+++ b/tests/sync/metrics.rs
@@ -32,7 +32,7 @@ async fn test_prometheus_format_valid() {
     let relay = TestRelay::start().await;
     tokio::time::sleep(Duration::from_millis(500)).await;
 
-    let metrics = fetch_metrics(&relay.url())
+    let metrics = fetch_metrics(relay.url())
         .await
         .expect("Failed to fetch metrics");
 
@@ -67,7 +67,7 @@ async fn test_metrics_availability_during_sync() {
 
     // Make multiple metrics requests while sync is active
     for i in 0..3 {
-        let metrics = fetch_metrics(&sync_relay.url()).await;
+        let metrics = fetch_metrics(sync_relay.url()).await;
         assert!(
             metrics.is_ok(),
             "Metrics request {} should succeed during sync",
@@ -135,7 +135,7 @@ async fn test_metric_values_are_numeric() {
     let relay = TestRelay::start().await;
     tokio::time::sleep(Duration::from_millis(500)).await;
 
-    let metrics = fetch_metrics(&relay.url())
+    let metrics = fetch_metrics(relay.url())
         .await
         .expect("Should fetch metrics");