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.

.env.example

@@ -0,0 +1,20 @@
+# Nostr Configuration
+VITE_NOSTR_RELAYS=["wss://relay.damus.io","wss://relay.snort.social"]
+VITE_ADMIN_PUBKEYS=["your-admin-pubkey-here"]
+
+# API Configuration
+VITE_API_BASE_URL=http://localhost:5000
+VITE_API_KEY=your-api-key-here
+
+# Push Notifications
+VITE_VAPID_PUBLIC_KEY=your-vapid-public-key
+VITE_PUSH_NOTIFICATIONS_ENABLED=true
+
+# Support
+VITE_SUPPORT_NPUB=your-support-npub
+
+# Market Configuration
+VITE_MARKET_NADDR=naddr1qqjxgdp4vv6rydej943n2dny956rwwf4943xzwfc95ekyd3evenrsvrrvc6r2qf8waehxw309akxucnfw3ejuct5d96xcctw9e5k7tmwdaehgunjv4kxz7f0v96xjmczyqrfrfkxv3m8t4elpe28x065z30zszaaqa4u0744qcmadsz3y50cjqcyqqq82scmcafla
+VITE_MARKET_RELAYS=["wss://relay.damus.io","wss://relay.snort.social","wss://nostr-pub.wellorder.net"]
+VITE_LIGHTNING_ENABLED=true
+VITE_MARKET_DEFAULT_CURRENCY=sat