Add initial files for Audio Dashboard Management System

- Created .env.example for environment variable configuration.
- Added docker-compose.yml for service orchestration.
- Implemented frequency response extraction in extract_frequency_response.py and convert_to_frequency_db.py.
- Generated output files: frequency_response_detailed.json, frequency_response_points.json, frequency_response.csv, and frequency_response_curve.png.
- Included sample measurement data for FiiO FA19 in CSV format.

frontend/nginx.conf

@@ -0,0 +1,30 @@
+server {
+    listen 80;
+    server_name localhost;
+    root /usr/share/nginx/html;
+    index index.html;
+
+    # Gzip compression
+    gzip on;
+    gzip_types text/plain text/css application/json application/javascript text/xml application/xml application/xml+rss text/javascript;
+
+    # API proxy to backend
+    location /api {
+        proxy_pass http://backend:8000;
+        proxy_set_header Host $host;
+        proxy_set_header X-Real-IP $remote_addr;
+        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+        proxy_set_header X-Forwarded-Proto $scheme;
+    }
+
+    # Handle Vue Router history mode
+    location / {
+        try_files $uri $uri/ /index.html;
+    }
+
+    # Cache static assets
+    location ~* \.(js|css|png|jpg|jpeg|gif|ico|svg|woff|woff2|ttf|eot)$ {
+        expires 1y;
+        add_header Cache-Control "public, immutable";
+    }
+}