feat(core): provide requests to skipped callbacks

[AkhilTrivediX]

Summary

• pass the full Request to onSkippedRequest instead of a URL string
• preserve request metadata for skips caused by filters, robots.txt, limits, crawl depth, and redirects
• update the crawl-depth coverage to verify userData reaches the callback

Why

onSkippedRequest previously discarded request metadata, which made it impossible for handlers to inspect fields such as userData. This follows the v4 API direction in #3801: callers receive the request object and can read its URL from request.url.

Validation

• corepack yarn eslint packages/basic-crawler/src/internals/basic-crawler.ts packages/browser-crawler/src/internals/browser-crawler.ts packages/core/src/enqueue_links/enqueue_links.ts packages/core/src/enqueue_links/shared.ts packages/http-crawler/src/internals/http-crawler.ts packages/playwright-crawler/src/internals/adaptive-playwright-crawler.ts test/core/crawlers/basic_crawler.test.ts
• corepack yarn tsc-check-tests
• corepack yarn vitest run test/core/crawlers/basic_crawler.test.ts --silent (68 passed)

Closes #3801