v1.0.182
feat: chat backend selector (Claude <-> Codex) in settings
Adds a Chat backend dropdown to ChatSettingsSection — flip chat between
Claude (Claude Code, curated tools) and Codex (OpenAI subscription, native
tools). When Codex is selected, an optional model field + an explainer of
the codex login / CODEX_HOME auth on the NAS. Saves to the existing
chat.{backend,codexModel} settings API. Completes the swappable chat
backend (engine verified live on the sub).