Fix release audit and cut v0.1.2

[sionsmith]

Summary

• bump semrush-rs to 0.1.2 and add changelog notes so auto-tag can publish a new release
• update governor/indicatif lock paths to remove RustSec warnings for rand 0.9.2 and number_prefix
• replace the Node-based RustSec action with a pinned direct cargo-audit run that denies warnings
• add a macOS MSRV release-target check for Rust 1.85
• update pinned actions/checkout usages to v5.0.1 for Node 24 runner compatibility

Verification

• cargo fmt --all -- --check
• cargo clippy --locked --all-targets -- -D warnings
• cargo test --locked --all-targets
• cargo install cargo-audit --version 0.22.1 --locked --force
• cargo audit --deny warnings
• RUSTFLAGS='-D warnings' rustup run 1.85.0 cargo check --locked --lib --bins
• cargo build --locked --release --bin semrush
• workflow YAML parse + git diff --check