Agent Skills: sk-prompt-small-model

Per-model prompt-craft hub for small-model dispatch (DeepSeek-v4-pro + Kimi-k2.7-code + MiniMax-M3 + MiMo-V2.5-Pro via cli-opencode). OWNS the per-model prompt-craft profiles in references/models/ (framework + scaffold + gotchas, mirroring model_profiles.json); executor MECHANICS (binary flags, invocation wrappers) stay in cli-opencode. Advisor co-surfaces it with that executor.