Pinned helper package: host and cross-build checkpoint

Observed 2026-09-23, branch implement/omarchy-themes, based on icon-landed master fd8fcf32. Upstream helper/template source is Omarchy Quattro 28ceaae70ebac3a0edcc21f2faa77a90dc6d404c, with byte hashes and the single path patch documented in nix/omarchy-theme-tools/SOURCE.md.

Commands and outcomes:

python3 tests/test_omarchy_theme_tools.py
  PASS: 2 host tests; original-byte manifest and patched-versus-path-adjusted
  original algorithm generated tree parity under disposable staging paths.
nix build .#omarchy-theme-tools --max-jobs 1 --cores 4 --no-link --print-out-paths
  PASS: /nix/store/2l3cmjv3i2yzcnibx2sjjm6j5nzwqblf-omarchy-theme-tools-28ceaae7
nix path-info -S /nix/store/2l3cmjv3i2yzcnibx2sjjm6j5nzwqblf-omarchy-theme-tools-28ceaae7
  66,767,856 bytes closure size
nix-store -q --requisites /nix/store/2l3cmjv3i2yzcnibx2sjjm6j5nzwqblf-omarchy-theme-tools-28ceaae7 | wc -l
  17 store paths
nix hash path /nix/store/2l3cmjv3i2yzcnibx2sjjm6j5nzwqblf-omarchy-theme-tools-28ceaae7
  sha256-/GTMIJlNG3cgIGgN1EtKX7N2EbwSs/q79s+gtv4XwIM=

This proves package construction and host helper output parity. It does not prove source checkout acquisition, theme activation, installed client integration, board appearance, performance, or reboot persistence. The package is an opt-in flake output and is not in the normal image closure.