Adds a Gitea Actions workflow that runs `cargo deny --locked check` on
every push to main and every PR, so the deny.toml policy (advisories,
bans, licenses, sources) is enforced automatically rather than by hand.
Runs on a locked tree so the pinned versions in Cargo.lock are what get
audited; a poisoned dependency release can't reach CI until Cargo.lock is
deliberately updated. cargo-deny is pinned to 0.19.9 via a prebuilt binary.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>