feat: Add Spanish locale support #169

Spanish is spoken by over 500 million people worldwide. Adding Spanish locale support will significantly expand the application's reach to Spanish-speaking developers across Latin America, Spain, and beyond.

Overview

Spanish will be added as a new supported locale with the language code es. Spanish uses left-to-right (LTR) layout, making this a straightforward addition similar to French.

Tasks

• Create a new locale file locales/es.json with all translation keys from locales/en.json translated to Spanish.
• Update lib/i18n-core.ts to add es to the supportedLocales array.
• Add Spanish entry to the localeMeta object in lib/i18n-core.ts with the following configuration:

  es: { dir: "ltr", label: "Español" }

• Test the language switcher to ensure Spanish appears in the dropdown menu.
• Test the application with Spanish locale selected to ensure all UI elements display correctly.
• Verify that all text content renders properly without layout issues.
• Update CONTRIBUTING.md with instructions for translating content to Spanish (if not already documented in the localization guide).

Translation Keys

All translation keys from the existing English locale must be translated to Spanish. The keys include:

• Application titles and subtitles
• Error messages
• UI labels and buttons
• Explanations and descriptions
• Comparison metrics
• Community contribution labels
• And more (reference locales/en.json for the complete list)

Testing

• Language switcher displays "Español" correctly.
• All pages render without errors when Spanish is selected.
• No layout shifts or broken styling in LTR mode.
• All Spanish translations are grammatically correct and contextually appropriate.