feat(translations): add Armenian translations (#1604)

## Summary

Adds default validation error translations for Armenian (`hy`).

The translations use modern Eastern Armenian with a neutral, formal UI
style. Field names are kept in quotation marks and used in constructions
such as `«{0}» դաշտը ...` so translated or technical field names do not
need Armenian case suffixes.

## What is included

- Armenian translations for all validation tags currently present in
`translations/en/en.go`
- Type-specific messages for strings, numbers, collections, and
date/time values
- Armenian cardinal plural registrations for character and item counts
- Tests covering registration, required fields, email, string and
collection length, numeric limits, cross-field comparison, `oneof`,
`datetime`, and plural forms

## Notes

- Translation package: `translations/hy`
- Locale used by tests: `github.com/go-playground/locales/hy`
- Technical identifiers such as URL, URI, UUID, CIDR, JSON, JWT, ISBN,
and RFC names are preserved

## Validation

- `gofmt` applied
- Translation tag/key parity checked against `translations/en/en.go`
- Full repository test suite should run in CI

Author: tigran90