feat: enhance Docker and Nginx configurations for security hardening and improved directory management

backend/Dockerfile

@@ -1,19 +1,56 @@
-# Backend build
-FROM node:25-slim AS builder
-WORKDIR /app
-COPY package.json tsconfig.json ./
-COPY src ./src
-RUN npm install
-RUN npm run build
-RUN npm prune --omit=dev
+# =============================================================================
+# BACKEND DOCKERFILE - Security Hardened
+# =============================================================================
+# Security measures applied:
+# - Non-root user execution
+# - Multi-stage build (minimal runtime image)
+# - No shell in final image (distroless)
+# - Read-only filesystem compatible
+# - No unnecessary packages
+# - Specific image versions pinned
+# =============================================================================
+
+# -----------------------------------------------------------------------------
+# Stage 1: Builder
+# -----------------------------------------------------------------------------
+FROM node:22-slim AS builder
 
-# Runtime
-FROM node:25-slim AS runner
 WORKDIR /app
+
+# Install dependencies first (better layer caching)
+COPY package.json package-lock.json* ./
+RUN npm ci --ignore-scripts
+
+# Copy source and build
+COPY tsconfig.json ./
+COPY src ./src
+RUN npm run build
+
+# Remove dev dependencies for smaller image
+RUN npm ci --omit=dev --ignore-scripts && \
+    npm cache clean --force
+
+# -----------------------------------------------------------------------------
+# Stage 2: Production Runtime (Distroless - no shell, minimal attack surface)
+# -----------------------------------------------------------------------------
+FROM gcr.io/distroless/nodejs22-debian12 AS runner
+
+WORKDIR /app
+
+# Copy built application with correct ownership (nonroot = uid 65532)
+COPY --from=builder --chown=65532:65532 /app/node_modules ./node_modules
+COPY --from=builder --chown=65532:65532 /app/dist ./dist
+COPY --from=builder --chown=65532:65532 /app/package.json ./
+
+# Environment configuration
 ENV NODE_ENV=production
-COPY --from=builder /app/node_modules ./node_modules
-COPY --from=builder /app/dist ./dist
-COPY package.json .
+ENV PORT=3000
+
+# Expose application port
 EXPOSE 3000
-# Run database setup before starting the server
-CMD ["sh", "-c", "mkdir -p /app/data && node dist/db/migrate.js && node dist/index.js"]
+
+# Run as non-root user (distroless default user)
+USER nonroot
+
+# Start application - migrations handled in index.ts
+CMD ["dist/index.js"]