MiMo provider: dynamic model catalog and V2.6 series support #1761

Problem

Xiaomi released the MiMo-V2.6 series (mimo-v2.6-pro, mimo-v2.6-flash, mimo-v2.6-pro-ultraspeed) on 2026-09-22, and mimo-v2.5-pro / mimo-v2.5 stop working on 2026-10-21 10:00 (GMT+8) per the deprecation notice.

The Zoo Code MiMo provider shipped a hardcoded 2-model catalog, so:

• V2.6 models are invisible unless users reconfigure MiMo as an OpenAI-compatible provider.
• After the v2.5 EOL date, the shipped default model stops working.

Expected

• The dedicated MiMo provider discovers models dynamically from the account's GET {baseUrl}/models response (same router-model pipeline as DeepSeek/Moonshot).
• The static catalog carries V2.6 entries (1M context, 128K max output, official pay-as-you-go pricing) with mimo-v2.6-pro as the default.
• Model selection in settings and the task header resolves specs correctly before the dynamic catalog arrives.

Actual

Static 2-model catalog only (mimo-v2.5-pro, mimo-v2.5); V2.6 models not selectable.

Fix

Implemented in PR #1748:

• mimo added to dynamicProviders; getMimoModels fetcher with four-endpoint Xiaomi allowlist enforced at the network boundary.
• V2.6 series added to packages/types catalog; default moved to mimo-v2.6-pro.
• Webview merges fetched catalog with static fallback (useSelectedModel, settings ModelPicker).
• Task header context window fix: static-catalog fallback while router models are unavailable (deepseek/moonshot/mimo).

Acceptance criteria

• MiMo provider lists account-visible models without an extension update.
• mimo-v2.6-pro is the default and works out of the box.
• Task header shows the real 1M context window for MiMo models.
• CI green on PR feat(mimo): fetch MiMo model catalog dynamically and add V2.6 series #1748.