Prepare 0.6.0 release

[Marc-André Moreau (mamoreau-devolutions)]

Summary

• add agent-friendly key/value filter support and structured CLI execution options
• add parser and end-to-end CLI coverage for argument handling, exit codes, and output contracts
• bump Rust and NuGet package versions to 0.6.0

Validation

• cargo fmt --all --check
• cargo clippy --workspace --all-targets
• cargo test --workspace