feat: add Spanish language support

Added complete Spanish (es) translation for the Biblical Guide application:
- Created messages/es.json with full Spanish translations
- Updated i18n.ts to include Spanish locale
- Updated middleware.ts to handle Spanish routes
- Added Spanish to language options in all locale files

Users can now access the app in Spanish at /es/* routes and select Spanish from the language settings.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

i18n.ts

@@ -1,13 +1,15 @@
 import {getRequestConfig} from 'next-intl/server';
 import ro from './messages/ro.json';
 import en from './messages/en.json';
+import es from './messages/es.json';
 
 // Can be imported from a shared config
-export const locales = ['en', 'ro'] as const;
+export const locales = ['en', 'ro', 'es'] as const;
 
 const messages = {
   ro,
-  en
+  en,
+  es
 } as const;
 
 export default getRequestConfig(async ({locale}) => {