[Feature]: Add ASR modality and Xiaomi MiMo Token Plan preset

[Jamartin-create]

Problem or Motivation

The Token Plan framework (lib/config/token-plan-presets.ts) is explicitly data-driven — adding a vendor is supposed to be "one entry here, no code changes" — but its modality set is fixed to llm | image | video | tts | webSearch, and ASR is called out in a comment as deliberately omitted ("ASR is omitted = not adapted").

Xiaomi MiMo's Token Plan is exactly the kind of plan the framework exists for: one tp- key authenticates against regional Token Plan clusters (token-plan-cn/sgp/ams.xiaomimimo.com) and covers LLM (mimo-v2.5-pro, mimo-v2.5), TTS (mimo-v2.5-tts family), and ASR (mimo-v2.5-asr). Without an ASR modality, one third of the plan's value is unreachable through the one-click apply flow, and users must hand-fill the ASR provider afterwards.

Proposed Solution

1. Add 'asr' to the modality framework:
   • TokenPlanModality and MODALITY_ORDER gain 'asr'.
   • apply-token-plan.ts: TokenPlanActions gains setASRProviderConfig; applyModality / removeModality handle asr symmetrically to tts (fill key + base URL + default model on apply; clear and disable on remove).
   • Settings UI (token-plan-settings.tsx): an ASR tab with a microphone icon and the existing settings.asrSettings label, actions wired through.
2. Add the xiaomi-mimo preset (category: 'token_plan'):
   • llm → provider xiaomi, https://token-plan-cn.xiaomimimo.com/v1, curated models mimo-v2.5-pro, mimo-v2.5
   • tts → provider xiaomi-tts, same base URL, default model mimo-v2.5-tts
   • asr → provider xiaomi-asr, same base URL, default model mimo-v2.5-asr
   • apiKeyPlaceholder: 'tp-...', icon /logos/xiaomi.svg, link https://mimo.mi.com
   • A comment documents that tp- keys authenticate only against Token Plan hosts (the pay-as-you-go api.xiaomimimo.com host rejects them), and that users in other regions can switch the base URL to the SGP/AMS cluster after applying.

Acceptance Criteria

• A user can select the Xiaomi MiMo Token Plan preset, paste one tp-... key, and have LLM + TTS + ASR all configured and enabled in one click
• The Token Plan settings page shows an ASR tab for presets that declare it
• Removing the plan clears the key and disables all three modalities
• Existing presets (MiniMax, Volcengine Ark) behave exactly as before

Alternatives Considered

• Ship the preset without the ASR modality: leaves the framework's "one key, every modality" promise half-kept for this vendor, and the ASR gap would need exactly this framework change later anyway.

Area

Model / provider integration

Additional Context

• Depends on [Feature]: Support Xiaomi MiMo TTS and ASR providers #1429 for the xiaomi-tts / xiaomi-asr provider implementations (referenced by string id, so this compiles independently; suggested merge order: after [Feature]: Support Xiaomi MiMo TTS and ASR providers #1429).