fix: docker build - use root context for monorepo workspaces

- Change build context from ./frontend|backend to root (.)
- Update Dockerfiles to copy from correct paths
- Use npm install instead of npm ci (workspaces share root lockfile)
- Remove obsolete version attribute from docker-compose.yml

Fixes npm ci errors when package-lock.json is at workspace root.

frontend/Dockerfile

@@ -3,16 +3,18 @@ FROM node:20-alpine AS builder
 
 WORKDIR /app
 
-# Copy package files
+# Copy root package files for workspace install
 COPY package*.json ./
+COPY frontend/package*.json ./frontend/
 
-# Install dependencies
-RUN npm ci
+# Install dependencies using npm install (no individual lockfile in workspace)
+RUN npm install --legacy-peer-deps
 
-# Copy source code
-COPY . .
+# Copy frontend source
+COPY frontend/ ./frontend/
 
 # Build Next.js app
+WORKDIR /app/frontend
 RUN npm run build
 
 # Production stage
@@ -22,14 +24,17 @@ WORKDIR /app
 
 # Copy package files
 COPY package*.json ./
+COPY frontend/package*.json ./frontend/
 
-# Install production dependencies only
-RUN npm ci --only=production
+# Install production dependencies
+RUN npm install --legacy-peer-deps --omit=dev
 
 # Copy built files from builder
-COPY --from=builder /app/.next ./.next
-COPY --from=builder /app/public ./public
-COPY --from=builder /app/next.config.js ./
+COPY --from=builder /app/frontend/.next ./frontend/.next
+COPY --from=builder /app/frontend/public ./frontend/public
+COPY --from=builder /app/frontend/next.config.js ./frontend/
+
+WORKDIR /app/frontend
 
 # Expose port
 EXPOSE 3000