Enable optional table locking for SQL Server bulk loads

[mag1cfrog]

Summary

• expose a connected-client method for enabling and disabling the SQL Server table lock on bulk load option
• safely quote table names and document the required fallback and cleanup contract
• verify option state across the SQL Server compatibility test matrix

Validation

• cargo fmt --check
• cargo clippy --all-targets --all-features -- -D warnings
• cargo test --all-features
• cargo doc --no-deps --all-features
• SQL Server 2017 compatibility level 100 probe