ci: add explicit lint check

[omribz156]

Summary:

• Add a first-class lint Make target for formatting, cargo sort --check, and Clippy checks.
• Add a dedicated GitHub Actions lint job so formatting/Clippy failures show up directly in CI.
• Make both library and integration-test Clippy runs fail on any warning with --deny warnings.

Verification:

• actionlint .github\workflows\ecdysis.yml
• cargo install cargo-sort --locked
• cargo fmt -- --check
• cargo sort --check
• cargo fmt --manifest-path integration_tests\Cargo.toml -- --check
• cargo sort --check integration_tests
• git diff --check

I could not run make lint in this Windows workspace because make is not installed. I also could not complete the Clippy commands locally because the crate uses Unix-only APIs (std::os::unix, Tokio Unix sockets/signals), and this workspace fails before linting; the new CI job runs on ubuntu-latest.

Fixes #17.

This was implemented with Codex assistance, with the patch kept focused on the CI lint gate.