fix: pass VITE_API_URL as build arg in Dockerfile

frontend/Dockerfile

@@ -5,6 +5,13 @@ COPY package.json ./
 RUN npm install
 
 COPY . .
+
+ARG VITE_API_URL=https://api.janichat.ru
+ARG VITE_WS_URL=wss://api.janichat.ru
+
+ENV VITE_API_URL=$VITE_API_URL
+ENV VITE_WS_URL=$VITE_WS_URL
+
 RUN npm run build
 
 FROM nginx:alpine