The desktop model picker had no way to force a fresh model fetch: model.options
went through the 1h-cached provider_models_cache.json, and there was no flag to
bust it. When a provider's cached list expired and its next live fetch failed,
the picker fell back to the curated static list — silently dropping live-only
models (e.g. OpenCode Zen's free tier like deepseek-v4-flash-free) the user had
been using.
- Thread refresh through model.options (RPC + REST /api/model/options) ->
build_models_payload -> list_authenticated_providers, which calls
clear_provider_models_cache() up front when set so every row re-fetches live.
- Add a 'Refresh Models' control to the desktop picker (5-locale i18n, spinning
sync icon). Normal opens leave refresh=false to stay snappy on the cache.
Verified: stale cache hides deepseek-v4-flash-free -> refresh busts it -> live
re-fetch surfaces it. refresh=false never touches the cache.
