Integrate @decodo/sdk-ts and update CI for sibling checkout

[paulius-krutkis-dcd]

Summary

• Replace the CLI's custom HTTP client and web scraping wrapper with @decodo/sdk-ts (DecodoClient, SDK error types, typed scrape requests).
• Remove duplicated platform code: HttpClient, local error classes, request/response types, and WebScrapingApi.
• Update auth validation to call client.webScrapingApi.scrape() with Target.Universal (imported as ScrapeTarget to avoid a Biome duplicate-key lint).
• Wire CI to check out and build Decodo/sdk-ts alongside the CLI until the SDK is published to npm; compile committed src/generated only (codegen needs gitignored decodo.ir.json).

Notes

• x-integration is still "sdk-ts" in the SDK (SCR-3150); tests reflect that. INTEGRATION_HEADER = "cli" remains for when the SDK supports it.
• Temporary CI/dev setup uses file:../sdk-ts and a separate sdk-ts checkout. TODOs mark what to remove once @decodo/sdk-ts is on npm.

Test plan

• pnpm lint
• pnpm typecheck
• pnpm test
• CI passes with dual checkout and compile-only sdk-ts build