feat: Secure SMS verification with Redis (Predis)

- Added Predis library for Redis connection (no PHP extension required)
- Server-side SMS code generation and storage in Redis
- Rate limiting and brute-force protection
- Integration with n8n webhook for SMS sending
- Environment variables moved to .env file
- Fixed policy verification endpoint
- Added file-based fallback if Redis unavailable

composer.json

@@ -0,0 +1,5 @@
+{
+    "require": {
+        "predis/predis": "^3.3"
+    }
+}