build(types): improve type safety in validation util

[google-labs-jules]

This commit improves the type safety in the getGeoCountryArgParser function in src/utils/validation.ts by adding explicit types to the function parameters. This removes a @ts-expect-error and resolves an implicit any type error.

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PR created automatically by Jules for task 11922417533878020770 started by @serhalp

[google-labs-jules]

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[github-actions]

📊 Benchmark results

Comparing with f5b1c11

• Dependency count: 1,052 (no change)
• Package size: 317 MB ⬇️ 0.00% decrease vs. f5b1c11
• Number of ts-expect-error directives: 371 ⬇️ 0.27% decrease vs. f5b1c11