feat(volcengine-tos): support presigned URLs

[ddupg]

Part of #752.

Summary

• Add query-based TOS signing for presigned URLs.
• Support security tokens, signed TOS headers, and explicit payload hashes.
• Add deterministic coverage and a credential-gated real TOS integration test.

Changes outside the TOS service only fix Rust 1.97 Clippy warnings exposed by CI.

Verification

• cargo fmt --all -- --check
• cargo clippy --workspace --all-targets --all-features -- -D warnings
• cargo test --no-fail-fast
• Real TOS presigned PUT/GET/DELETE
• OpenDAL TOS behavior suite: 54 passed on a versioning-enabled bucket

[ddupg]

@Xuanwo Could you help review this? thanks!