chore(libspot-rs): release 0.4.0-rc.1

[shenxiangzhuang]

Summary

• bump libspot-rs crate version to 0.4.0-rc.1
• update libspot-rs README and crate docs dependency snippets

Validation

• cargo fmt --check --manifest-path crates/libspot-rs/Cargo.toml
• cargo test --manifest-path crates/libspot-rs/Cargo.toml
• cargo clippy --manifest-path crates/libspot-rs/Cargo.toml --all-targets -- -D warnings
• cargo package --manifest-path crates/libspot-rs/Cargo.toml

[github-actions]

▸ Cross-implementation results

commit e06160f · Linux · release builds

Consistency (basic example)

Metric	C	Rust FFI	Pure Rust
Anomalies	90007	90007	90007
Excess	7829	7829	7829
Normal	49902164	49902164	49902164
Z	6.237668	6.237668	6.237668
T	6.236165	6.236165	6.236165

Benchmark (hyperfine --warmup 1 --runs 5)

Command	Mean [s]	Min [s]	Max [s]	Relative
raw C	1.005 ± 0.001	1.004	1.006	1.00
Rust FFI (libspot)	1.527 ± 0.008	1.520	1.538	1.52 ± 0.01
Pure Rust (libspot-rs)	1.212 ± 0.003	1.210	1.217	1.21 ± 0.00

_{updated by Test cross-implementation consistency}