v0.20.2

Added

• Add pricing and catalog support for latest frontier models: Gemini 3.8 Flash
  (gemini-3.8-flash), Anthropic Claude Fable 5.1 (claude-fable-5.1) and
  Mythos 5.1 (claude-mythos-5.1), and DeepSeek models (deepseek-v4.1-flash,
  deepseek-v4-flash, deepseek-v4-pro, deepseek-v3.2, deepseek-chat, and
  deepseek-r1).
• Map deepseek author slugs in OpenRouter routing policy to direct registered
  model identifiers, enabling hard budget preauthorization, registered price
  ceilings, and accurate ledger accounting for OpenRouter DeepSeek models.
• Set deepseek/deepseek-v4.1-flash as the recommended default model when
  OpenRouter is configured, and provide OpenRouter models and pricing in
  distill provider list openrouter.
• Support global fallback workflow budgets (default=<usd> and all=<usd>)
  in DISTILL_COST_WORKFLOW_BUDGETS so unlisted commands inherit a single
  safety ceiling against unexpected spend.