ARM64 Docker images: published but untested — reports from ARM hardware wanted

[TickTockBent]

Summary

The Docker publish workflow only builds linux/amd64 images. ARM64 users (Apple Silicon Macs, AWS Graviton, other ARM servers) must run under emulation, which is slow.

Proposed Solution

Add linux/arm64 platform to the Docker multi-platform build.

Changes needed:

• Update the GitHub Actions workflow to use docker buildx with --platform linux/amd64,linux/arm64
• Verify Puppeteer/Chromium availability on ARM64 — Chromium has ARM64 Linux builds but Puppeteer's bundled download may need configuration
• Test both Alpine and Debian variants on ARM64
• May need to use chromium system package on Alpine ARM64 instead of Puppeteer's bundled download

Considerations:

• Cross-compilation builds are slower; consider using native ARM64 runners if available
• The Alpine image may need different Chromium packaging for ARM64

Context

Listed on the existing feature roadmap in README.md.

[TickTockBent]

PR #281 adds linux/arm64 to both published images (Debian :latest and :alpine).

Status: built, not tested. Both images cross-build for arm64 under QEMU, and the Debian arm64 image correctly carries Debian's chromium (Chrome for Testing has no arm64 Linux build) with the entrypoint pointing Puppeteer at it. But Chromium can't be launched under qemu-user emulation, and the maintainer has no ARM hardware, so nobody has run these images end to end on Apple Silicon, Graviton, or a Pi.

If you run Charlotte on ARM, please reply here with:

• image tag (:latest / :alpine and version)
• host (M-series Mac / Graviton / Raspberry Pi / other) and Docker version
• whether docker run ... charlotte doctor --http passes, and whether a navigate + observe round-trip works
• the first ~20 lines of container output if anything fails

This issue stays open until there's a confirmed working report; it'll then be closed and the "untested" warning in the Docker docs removed.

// ticktockbent