chore: speed up multi-arch Docker builds with cargo-zigbuild

[mikkeldamsgaard]

Summary

• Replace QEMU-emulated arm64 compilation (~44 min) with native cross-compilation using cargo-zigbuild + sccache, reducing release workflow from ~50 min to ~8-12 min
• Switch mysql crate from native-tls (OpenSSL) to rustls-tls, eliminating ~60 transitive dependencies while keeping binary size at ~5 MB
• Split release workflow into parallel test → build (matrix amd64+arm64) → docker → publish jobs; crates.io publish now runs after Docker images are pushed

Test plan

• cargo test --all — 36 tests pass (unit + integration)
• cargo clippy -- -D warnings — no warnings
• cargo fmt --check — formatted
• dprint check — formatted
• make cross-build — produces correct static ELF binaries for both arches (file bin/initium-amd64 bin/initium-arm64)
• Docker build + run for all 4 images (initium + jyq × amd64 + arm64) — --help works, jq/yq available in jyq variant
• Push a test tag to verify full release workflow in CI

🤖 Generated with Claude Code

[Copilot]

Pull request overview

This PR replaces QEMU-emulated multi-arch Docker builds with native cross-compilation using cargo-zigbuild and sccache, and switches the mysql crate from OpenSSL (native-tls) to rustls-tls to eliminate the OpenSSL dependency. The release and CI workflows are restructured into parallel jobs for faster execution.

Changes:

• Dockerfiles simplified from multi-stage Rust builds to minimal images that COPY pre-built, cross-compiled binaries; Makefile gains cross-build and docker-multiarch targets
• CI and release workflows split into parallel test/build jobs using cargo-zigbuild + sccache, with Docker and crates.io publish as downstream jobs
• mysql crate switched to rustls-tls with minimal-rust and buffer-pool features, removing ~60 transitive dependencies (OpenSSL, native-tls, etc.)

Reviewed changes

Copilot reviewed 9 out of 10 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
Dockerfile	Replaced multi-stage Rust build with minimal alpine certs stage + scratch, copying pre-built arch-specific binary
Dockerfile.jyq	Same simplification: alpine base with pre-built binary COPY using TARGETARCH
Makefile	Added cross-build and docker-multiarch targets; build now creates bin/ dir
Cargo.toml	Switched mysql crate to rustls-tls with minimal-rust and buffer-pool features
Cargo.lock	Updated lock file reflecting dependency tree changes
.github/workflows/release.yml	Split into test, build (matrix), docker, publish jobs with zigbuild + sccache
.github/workflows/ci.yml	Build job now cross-compiles for both arches with zigbuild + sccache
.dockerignore	Removed bin/ exclusion so Docker context includes pre-built binaries
README.md	Added Development section with cross-compilation prerequisites
CHANGELOG.md	Documented all workflow and build changes

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[mikkeldamsgaard]

Addressing Copilot review: removed obsolete docker-build and docker-push Makefile targets (the new Dockerfile expects bin/initium-${TARGETARCH} from cross-build). Updated README to reference make docker-multiarch instead.