fix: simplify match arms to satisfy clippy manual-unwrap-or-default and manual-unwrap-or
Two match expressions in crates/replication/src/runtime.rs triggered
clippy lints (manual-unwrap-or-default, manual-unwrap-or) with the
project's -D warnings policy. Replace them with the idiomatic
.unwrap_or_default() and .unwrap_or() calls.