fix: configure nginx proxy for API calls to fix cross-origin issues

Problem:
Frontend was calling localhost:8000 for API, but when accessing
from Windows (192.168.254.79:8888), the browser tried to connect
to localhost on the Windows machine instead of the server.

Solution:
1. Added nginx.conf with proxy configuration for /api/ routes
2. Updated Dockerfile to copy nginx.conf to container
3. Changed api.ts baseURL from 'http://localhost:8000/api/v1' to '/api/v1'
4. Nginx now proxies all /api/ requests to backend:8000

This allows the frontend to work correctly from any client
by using relative paths that nginx proxies to the backend.

frontend/Dockerfile

@@ -23,8 +23,8 @@ FROM nginx:alpine
 # Copy built assets
 COPY --from=builder /app/dist /usr/share/nginx/html
 
-# Copy nginx config (optional)
-# COPY nginx.conf /etc/nginx/conf.d/default.conf
+# Copy nginx config with API proxy
+COPY nginx.conf /etc/nginx/conf.d/default.conf
 
 EXPOSE 80
 

frontend/nginx.conf

@@ -0,0 +1,45 @@
+server {
+    listen 80;
+    server_name localhost;
+    root /usr/share/nginx/html;
+    index index.html;
+
+    # Gzip compression
+    gzip on;
+    gzip_vary on;
+    gzip_min_length 1024;
+    gzip_types text/plain text/css text/xml text/javascript application/javascript application/xml+rss application/json;
+
+    # Proxy API requests to backend
+    location /api/ {
+        proxy_pass http://backend:8000/api/;
+        proxy_http_version 1.1;
+        proxy_set_header Upgrade $http_upgrade;
+        proxy_set_header Connection 'upgrade';
+        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;
+        proxy_cache_bypass $http_upgrade;
+    }
+
+    # Serve static files
+    location /assets/ {
+        expires 1y;
+        add_header Cache-Control "public, immutable";
+        try_files $uri =404;
+    }
+
+    # Handle client-side routing - serve index.html for all routes
+    location / {
+        try_files $uri $uri/ /index.html;
+        add_header Cache-Control "no-cache";
+    }
+
+    # Health check endpoint
+    location /health {
+        access_log off;
+        return 200 "healthy\n";
+        add_header Content-Type text/plain;
+    }
+}

frontend/src/lib/api.ts

@@ -1,7 +1,7 @@
 import axios from 'axios';
 
 const api = axios.create({
-  baseURL: import.meta.env.VITE_API_URL || 'http://localhost:8000/api/v1',
+  baseURL: '/api/v1',
   headers: {
     'Content-Type': 'application/json',
   },