feat (SITES-39993): Add read-only Google Search Console API methods

[ssilare-adobe]

Summary

Extends the Google Client with additional read-only API methods from the Google Search Console API v1, completing coverage of all available read-only endpoints.

Changes

New Methods

• getSite(siteUrl) - Retrieves information about a specific site including URL and permission level
• getSitemap(sitemapUrl) - Retrieves detailed information about a specific sitemap including submission date, errors, and warnings
• listSitemaps(sitemapIndex?) - Lists all sitemaps for a site with optional sitemap index filtering

Improvements

• Updated row limit validation for search analytics from 1,000 to 25,000 rows to match API specifications
• Added TypeScript definitions for all new methods with comprehensive JSDoc comments
• Full input validation for all parameters including URL format and domain property support

Testing

• Added comprehensive test coverage for all new methods (36 tests total)
• Achieved 100% code coverage across statements, branches, functions, and lines
• Added edge case tests for error handling and validation

API Coverage

All read-only methods from Google Search Console API v1 are now implemented:

• Search Analytics: query
• Sites: get, list
• Sitemaps: get, list
• URL Inspection: index.inspect