fix: correct jitter range to ±25% and fix abort.rs doc — review findings

crates/zesdex-backend/src/app/util/abort.rs

@@ -1,7 +1,8 @@
 //! Shared abort-flag checks.
 //!
-//! The two variants (Option<Arc<AtomicBool>> and bare AtomicBool) are
-//! used across the agent runtime, subagent, workflow engine, and provider.
+//! Three variants (Option<Arc<AtomicBool>>, bare AtomicBool, and
+//! Option<&AtomicBool>) cover the agent runtime, subagent, workflow
+//! engine, and provider.
 
 use std::sync::atomic::{AtomicBool, Ordering};
 use std::sync::Arc;

crates/zesdex-backend/src/app/util/backoff.rs

@@ -13,10 +13,10 @@ use std::time::{Duration, SystemTime, UNIX_EPOCH};
 pub fn backoff_seconds(attempt: u32, max_secs: u64) -> Duration {
     let base_secs = (2u64).pow(attempt).min(max_secs);
     let quarter = (base_secs * 250_000_000).max(100_000_000); // 25% of base, min 100ms
-    let offset = jitter_ns(quarter);
-    // ±25%: offset in [0, quarter), so result = base - quarter/2 + offset
+    let offset = jitter_ns(quarter * 2); // [0, 50% of base)
+    // ±25%: offset in [0, 2×quarter), result = base + offset - quarter
     // which lies in [base - 25%, base + 25%).
-    let ns = base_secs * 1_000_000_000 + offset - quarter / 2;
+    let ns = base_secs * 1_000_000_000 + offset - quarter;
     Duration::from_nanos(ns)
 }