feat: 交付跨平台发布物与多架构镜像

[heyjunpenn]

Closes #22

Summary

• add PR-validated Linux x64/arm64 and macOS x64/arm64 release builds for both egresskit and egressd
• add real linux/amd64 + linux/arm64 Docker build/run smoke jobs and a tag-published multi-architecture GHCR image
• pin GitHub Actions, Dockerfile frontend, Node base image, Mihomo v1.19.30 assets, and both architecture SHA-256 values
• stamp archive versions from validated SemVer tags and attach four installable archives to GitHub Releases
• ship canonical Apache-2.0 and Mihomo GPL-3.0 attribution/license/source materials in archives and images
• document the v1 support matrix, official download channels, container boundary, and plaintext state-directory security boundary
• add co-located release contract tests and include them in pnpm verify

Verification

• pnpm verify (169 application tests + 8 release tests)
• actionlint v1.7.12 on the workflow
• real local Docker build and external /live probe: linux/arm64, Mihomo v1.19.30
• real local cross-platform Docker build and external /live probe: linux/amd64, Mihomo v1.19.30
• install generated package archive and execute both egresskit and egressd bins