feat(i18n): implement internationalization, Ukrainian localization support, and bump version to v1.2.0

[podlLev]

Overview

This PR introduces full internationalization (i18n) and localization (l10n) across the application, adding full support for Ukrainian alongside default message bundles. It dynamically resolves user request locales to fetch localized weather condition descriptions directly from OpenWeatherMap and translates frontend templates and weather condition labels.

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Key Changes

• Internationalization Infrastructure & Message Bundles:

  • Encoding & Config: Configured Spring MessageSource with UTF-8 encoding to correctly parse internationalization character sets.
  • Message Bundles: Added default and Ukrainian (messages_uk.properties) message bundles to support UI localization.
  • View Localization: Refactored HTML views/templates to utilize localized i18n message keys instead of hardcoded UI strings.

• Weather API Localization Integration:

  • Locale Resolver: Implemented WeatherApiLocale to resolve active request locales and map them into API-compatible parameters.
  • Localized External Requests: Configured OpenWeatherMap client queries to request localized weather condition descriptions based on the resolved user locale.
  • Localized Weather Condition Labels: Added weather-condition.* translation keys for standardized weather condition mappings across the application.

• Testing & Release Management:

  • Locale Verification Tests: Added WeatherApiLocaleTest and updated WeatherApiClientTest with pinned LocaleContextHolder states to verify locale-aware API call resolution.
  • Version Bump: Bumped application version to 1.2.0 in preparation for release.