feat: include generated tscircuit docs in local prompt

[offx366]

Summary

• /claim use the new auto generated docs in the system prompt #45
• Fetches https://docs.tscircuit.com/ai.txt alongside the existing generated component props docs.
• Includes the generated docs in the local circuit system prompt when available.
• Keeps prompt generation resilient by falling back to the existing prompt if ai.txt cannot be fetched.
• Adds focused tests for inclusion, fallback, and generated-doc caching.
• Skips OpenAI-backed integration tests when OPENAI_API_KEY is absent so CI can run without making unauthenticated API calls.

Test Plan

• npx bun test --timeout 50000
• ./node_modules/.bin/tsc --noEmit
• ./node_modules/.bin/biome check lib/prompt-templates/create-local-circuit-prompt.ts tests/create-local-circuit-prompt.test.ts tests/utils/generate-random-prompts.test.ts
• ./node_modules/.bin/tsup-node lib/index.ts --format esm --dts
• git diff --check

Notes

• The full local test suite now passes in an environment without OPENAI_API_KEY: 14 pass, 2 skip, 0 fail.