feat: add AI SDK tools and crawl pages support

[FrancescoSaverioZuppichini]

Summary

• add @scrapegraphai/ai-sdk package with Vercel AI SDK tools and examples
• align SDK schemas/types with API shared schemas and add crawl pages support
• document API key setup, AI SDK usage, examples, and crawl page pagination
• update CI to install the AI SDK against the local root package while scrapegraph-js@2.2.0 is unpublished

Test plan

• bunx tsc --noEmit
• cd packages/ai-sdk && bun run check
• bun test tests/*.test.ts
• bun run build
• cd packages/ai-sdk && bun run build
• biome check on touched source/docs

Notes

• @scrapegraphai/ai-sdk depends on scrapegraph-js ^2.2.0, so installing the AI SDK also installs the JS SDK. Publish scrapegraph-js first.