Fix CI: Debian Docker repo detection, remove yay dependency, skip Docker in containers

[Copilot]

CI fails on Debian (wrong Docker repo URL) and Arch (missing yay). Docker-in-Docker adds unnecessary complexity.

Changes

• Docker install (41-docker.sh): Detect distro from /etc/os-release and use correct repo URL

  # Before: hardcoded ubuntu
  https://download.docker.com/linux/ubuntu/gpg
  
  # After: dynamic distro detection
  . /etc/os-release
  https://download.docker.com/linux/${ID}/gpg

• mise install (30-mise.sh): Use pacman instead of yay on Arch (mise is in extra repo)

  # Before
  yay -S --noconfirm mise
  
  # After
  sudo pacman -S --noconfirm mise

• Container detection (install + 41-docker.sh): Export DOTS_CONTAINER env var, skip Docker install in containers

  if [[ -f "/.dockerenv" ]] || grep -Eq 'docker|containerd' /proc/1/cgroup 2>/dev/null; then
      DOTS_CONTAINER="docker"
  fi

Original prompt

Summary

CI is failing on both Debian and Arch Linux Docker builds due to two separate issues.

---

Issue 1: Debian — Incorrect Docker Repository URL

File: script/install.d/41-docker.sh

The Docker APT repository is hardcoded to use the Ubuntu repository URL, but the Dockerfile uses Debian Bookworm as the base image. The error is:

E: The repository 'https://download.docker.com/linux/ubuntu bookworm Release' does not have a Release file.

bookworm is a Debian codename, not Ubuntu. Docker's repository structure differs between distributions.

Fix: Detect the distribution from /etc/os-release and use the correct repository URL (debian vs ubuntu).

---

Issue 2: Arch Linux — Missing yay AUR Helper

File: script/install.d/30-mise.sh

The Arch Linux branch attempts to use yay to install mise from the AUR:

pacman)
    yay -S --noconfirm mise
    ;;

The Docker image does not have yay installed, causing yay: command not found.

Fix: Use sudo pacman -S --noconfirm mise instead of yay. The mise package is available in the official Arch extra repository, so no AUR helper is required.

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Issue 3: Skip Docker installation inside containers

File: script/install and script/install.d/41-docker.sh

Docker-in-Docker adds unnecessary complexity for CI testing. The install script should detect when running inside a container and skip Docker installation.

Fix:

1. In script/install, add container detection alongside existing environment detection (after the Codespaces check around line 65):

# Detect container environment
export DOTS_CONTAINER=""
if [[ -f "/.dockerenv" ]] || grep -Eq 'docker|containerd' /proc/1/cgroup 2>/dev/null; then
    DOTS_CONTAINER="docker"
fi

2. In script/install.d/41-docker.sh, add a skip check using the new variable (after the Codespaces check):

# skip if in a container (Docker-in-Docker adds complexity)
[[ -n "$DOTS_CONTAINER" ]] && { log_warn "Skipping: Running inside container"; return 0; }

---

Acceptance Criteria

• Debian CI build passes (Docker install script correctly detects Debian vs Ubuntu)
• Arch Linux CI build passes (mise installs via pacman without yay)
• Docker installation is skipped when running inside a container
• All changes are idempotent and safe to re-run
• Changes follow project conventions (use [[ ]] for conditionals, export for environment variables)

This pull request was created from Copilot chat.

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