fix(ci): allow clippy::duration_suboptimal_units

Rust 1.95's new `duration_suboptimal_units` lint flags
`Duration::from_secs(N)` where N is divisible by 60 / 3600 (~50 sites
across retry/timeout code). Functionally identical to `from_mins`/
`from_hours`; the readability gain is marginal and the churn is real.
Allow the lint workspace-wide to unblock CI on rust 1.95 stable.

Author: lingcoder

Cargo.toml

@@ -189,6 +189,10 @@ option_if_let_else = "allow"
 or_fun_call = "allow"
 comparison_chain = "allow"
 if_same_then_else = "allow"
+# Stylistic-only; `Duration::from_secs(3600)` reads just as well as
+# `from_hours(1)`. The lint (rust 1.95+) fires across retry/timeout
+# code with no functional benefit.
+duration_suboptimal_units = "allow"
 
 [profile.dev]
 opt-level = 0