fix: remove stale Ax optimizer import

[haasonsaas]

Summary

• remove the unused AxMiPRO named import from evals/optimize-prompt.mjs
• keep the optimizer script compatible with @ax-llm/ax v20 module exports

Review feedback addressed

• build(deps): bump @ax-llm/ax from 19.0.45 to 20.0.0 #77: @ax-llm/ax v20 no longer exports AxMiPRO, so the eval script should not import it

Verification

• git diff --check
• symlinked the existing Kestrel node_modules into the fresh worktree, then ran node evals/optimize-prompt.mjs and confirmed it reaches the expected OPENROUTER_KEY guard instead of failing ESM import resolution

[cursor]

PR Summary

Low Risk
Low risk: removes an unused/stale named import to match @ax-llm/ax v20 exports, avoiding ESM import resolution failures without changing runtime behavior.

Overview
Updates the prompt optimizer script (evals/optimize-prompt.mjs) to stop importing AxMiPRO, leaving only AxAI so the file remains compatible with @ax-llm/ax v20 module exports.

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