Adopt werkpilot's CI compile-acceleration setup so builds are crates.io-
independent and cached across runs:
- Resolve crates.io deps through the self-hosted Kellnr mirror
(crates.meghsakha.com) via a .cargo/config.toml source replacement. Git deps
(tramiton-core) are unaffected.
- Back sccache with Hetzner S3 (breakpilot-sccache bucket, key prefix
compliance-scanner) instead of an ephemeral /tmp dir — persistent across CI
runs. Bump sccache to v0.10.0.
- Throttle cargo (CARGO_NET_RETRY, HTTP/1.1) so the ~670-crate download burst
doesn't 429 the mirror.
Requires repo secrets HETZNER_S3_ACCESS_KEY and HETZNER_S3_SECRET_KEY (same
bucket/creds as werkpilot). Closes#139.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>