Model retry alternative strategy plugin

Project overview

Automatic provider/model fallback chains for dsh (DeepSeek Harness): when an agent's LLM requests keep failing — retries exhausted, auth errors, quota exceeded, rate limiting (429) — the plugin switches provider/model along the fallback chain for the current role, and the current step/turn continues on the target model: tasks are not interrupted by model problems.

Add a fallbacks: section to the dsh settings document (default $DSHHOME/settings.yaml):

The command is read-only — it never mutates fallback state (no cooldown reset, no pending-switch writes). It registers through a conditional commands child, so it appears only when the host composes the slash-command registry — with no registry the command is silently unavailable (no top-level inject pollution). Output is zh by default (the host carries no per-session locale signal); the en dictionary lives in the same copy table. Mount-only (no dsh modification)