- Wire claude-fable-5 as a fourth tier on both proxy paths, with a
fable -> opus -> default fallback mirroring the official downgrade.
- Whitelist the fable- prefix for the Desktop 1.12603.1+ validator.
- Clarify fallbackModelHint (zh/en/ja/zh-TW): a blank tier on
third-party endpoints forwards the literal model name and 404s.
Refs #3980, #4026, #4049.
Polish the provider-level User-Agent override UI on the Claude and Codex forms.
- Add a shared CustomUserAgentField (label + input + preset dropdown + live
validation) so both forms stay in sync.
- Provide curated UA presets (Claude Code / Kilo Code families that pass
coding-plan UA whitelists per #3671); the first is Claude Code's real
`claude-cli/x (external, cli)` format. Whitelists gate on the name prefix,
not the version, so static values stay valid across upgrades.
- Expose presets via a dropdown to the right of the input (z-[200] so it
renders above the dialog layers) instead of inline chips.
- Move the field into the existing advanced/reasoning collapsibles.
- userAgent.ts mirrors the backend byte rule (reject only control chars;
non-ASCII is allowed) for a non-blocking inline hint.
- i18n for all four locales (zh/en/ja/zh-TW).
- Add `get_codex_oauth_models` Tauri command reusing the managed OAuth
access token to hit `chatgpt.com/backend-api/codex/models`; HTTP and
multi-shape JSON parsing live in `services::codex_oauth_models` so the
command stays thin.
- Unify the Claude form's "fetch models" button across normal / Copilot /
Codex OAuth presets, drop the auto-load effect for Copilot in favor of
explicit clicks, and guard against stale responses with a requestId ref.
- Add Vitest coverage for both Copilot and Codex OAuth paths asserting no
request on mount and the correct account id on click; add Rust unit
tests for the four model-list payload shapes.
Jianfeng Mei