feat: Add .env.example file and update Navbar for market navigation

- Introduce a new .env.example file for Nostr and API configuration, including settings for push notifications and market relays.
- Update Navbar.vue to include a new navigation item for the market, enhancing user access to market features.
- Extend localization support by adding market translations in English, Spanish, and French.

src/i18n/types.ts

@@ -5,6 +5,7 @@ export interface LocaleMessages {
     directory: string
     faq: string
     events: string
+    market: string
     login: string
     logout: string
   }