feat(frontend): add React chat UI with SSE parsing and source accordion

frontend/nginx.conf

@@ -0,0 +1,33 @@
+server {
+    listen 80;
+    server_name _;
+
+    root /usr/share/nginx/html;
+    index index.html;
+
+    # O backend responde o chat em SSE; o proxy não deve bufferizar a resposta.
+    location /api/ {
+        proxy_pass http://backend:8000;
+        proxy_http_version 1.1;
+        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_buffering off;
+        proxy_cache off;
+        proxy_read_timeout 300s;
+        proxy_send_timeout 300s;
+        chunked_transfer_encoding on;
+    }
+
+    location / {
+        try_files $uri $uri/ /index.html;
+    }
+
+    location ~* \.(js|css|woff2?|png|svg|ico)$ {
+        expires 30d;
+        add_header Cache-Control "public, immutable";
+        try_files $uri =404;
+    }
+}