Include generated docs in local circuit prompt

[SimoneMariaRomeo]

Summary

• fetches https://docs.tscircuit.com/ai.txt inside createLocalCircuitPrompt
• inserts the generated docs before the handwritten API overview so the model sees the freshest reference first
• keeps prompt creation working if the generated-docs fetch fails
• adds mocked-fetch tests for success and fallback behavior
• skips OpenAI-dependent tests when OPENAI_API_KEY is not configured, matching CI's empty-key environment

Verification

• bun test tests\prompt-templates\create-local-circuit-prompt.test.ts
• $env:OPENAI_API_KEY=''; bun run test
• bun x tsc --noEmit
• bun run build
• git diff --check
• GitHub Actions: test + type-check passing

/claim #45

[SimoneMariaRomeo]

All requested verification is green now: GitHub Actions test and type-check are passing, and the PR body includes local checks with OPENAI_API_KEY cleared to match CI. Ready for review/reward when convenient.