feat(google-sheets): add duplicate row detection and sheet sanitization utilities

[Ash0508]

✨ Summary

This PR adds two utility methods to the Google Sheets SDK:

• detectDuplicateRows: Finds duplicate rows in a sheet range
• sanitizeSheetData: Trims whitespace from all string values in a given range

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✅ What's Included

• src/sdk.ts: New utility functions added to the GoogleSheetsSdk class
• __tests__/sdk.test.ts: Unit tests added for both utility functions
• docs/duplicateRowsDetection.md: Documentation for detectDuplicateRows
• docs/sanitizeSheetData.md: Documentation for sanitizeSheetData
• package-info.json: readme_map updated with both new methods
• package.json, tsconfig.json: Minor adjustments to support local test/dev (if modified)

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🧪 Test Summary

• Run npx jest packages/google-sheets
• All test cases pass locally.

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📌 Notes

• Follows the Microfox contribution structure
• Naming conventions, typing, and zod schemas remain unchanged