fix: don't abort clean install when Homebrew prerequisites are missing

[Copilot]

On a clean Linux system (e.g. a fresh WSL distro) git/curl aren't present yet — they're installed later by the package-install script. The Homebrew setup script (run_once_before_05-install-homebrew.sh.tmpl) hard-failed with exit 1 on the missing dependency, aborting the entire chezmoi apply:

ERROR  [install-homebrew] Missing required dependencies: git
HINT   [install-homebrew]   sudo apt-get install -y git
chezmoi: .chezmoiscripts/linux/05-install-homebrew.sh: exit status 1

Since Homebrew is optional on Linux, a missing prerequisite should not tank the whole install.

Changes

• Auto-install prerequisites on Linux — the missing-deps branch now attempts apt-get/dnf install (Ubuntu/Debian and Fedora/RHEL/CentOS) when passwordless sudo is available, instead of only printing a hint.
• Graceful skip instead of abort — re-checks with command -v after the install attempt; if anything is still missing it logs which deps remain and exit 0, letting chezmoi apply continue (the package script installs git/curl shortly after).
• macOS unchanged — the non-Linux template branch keeps exit 1, since Homebrew is required there and git/curl ship with the system.
• Tests — added bats coverage in test-chezmoi-scripts.bats asserting the Linux auto-install commands exist and the script no longer hard-fails on missing deps.

Notes

• The apt-get/dnf calls use || true intentionally (script runs under set -euo pipefail); the subsequent STILL_MISSING re-check is the source of truth for per-dependency outcome and logging.
• One unrelated pre-existing test failure (package-utils: Windows package IDs can match by package suffix) is present on the base branch and untouched here.

[DevSecNinja]

@copilot can you fix the failing test?

[Copilot]

@copilot can you fix the failing test?

Fixed in 8582e50. The package-utils: Windows package IDs can match by package suffix test asserted mise for the windows platform, but mise is a Linux/WSL tool and isn't in the Windows winget list — so it always failed. Updated the test to use chezmoi, which is a real Windows package (twpayne.chezmoi) and genuinely exercises the reverse-DNS suffix matching. Full suite is green now.

@copilot can you fix the failing test?

Correction: the commit hash is 1a0f7d0 (not 8582e50).