Codex ship-gate (SILENT): both disk loaders dropped `aliases` (the save path
never persisted them), so a disk-cache hit — strict cold-path OR the new stale
fallback — served /api/models with empty aliases, silently breaking `/model
<alias>` slash-command resolution (static/commands.js resolves slash aliases
only from /api/models.aliases). Add _model_aliases_from_config() helper and
reconstruct aliases from current config in BOTH loaders (fixes the pre-existing
strict-loader gap too). Adds a regression test.
Co-authored-by: starship-s <starship-s@users.noreply.github.com>