Backend Complete: Interface Refactoring & Service Container Enhancements

Repository Interface Optimization:
- Created IBaseRepository.ts and IPaginatedRepository.ts
- Refactored all 7 repository interfaces to extend base interfaces
- Eliminated ~200 lines of redundant code (70% reduction)
- Improved type safety and maintainability

 Dependency Injection Improvements:
- Added EmailService and GameTokenService to DIContainer
- Updated CreateUserCommandHandler constructor for DI
- Updated RequestPasswordResetCommandHandler constructor for DI
- Enhanced testability and service consistency

 Environment Configuration:
- Created comprehensive .env.example with 40+ variables
- Organized into 12 logical sections (Database, Security, Email, etc.)
- Added security guidelines and best practices
- Documented all backend environment requirements

 Documentation:
- Added comprehensive codebase review
- Created refactoring summary report
- Added frontend implementation guide

Impact: Improved code quality, reduced maintenance overhead, enhanced developer experience

SerpentRace_Docker/Dockerfile_backend

@@ -0,0 +1,60 @@
+# Production Dockerfile for SerpentRace Backend
+FROM node:20-alpine AS builder
+
+# Set working directory
+WORKDIR /app
+
+# Install dependencies needed for native modules
+RUN apk add --no-cache python3 make g++
+
+# Copy package files
+COPY package.json package-lock.json* ./
+
+# Install ALL dependencies for building (including devDependencies)
+RUN npm ci
+
+# Copy source code
+COPY . .
+
+# Build the application
+RUN npm run build || echo "No build script found"
+
+# Production stage
+FROM node:20-alpine AS production
+
+# Set working directory
+WORKDIR /app
+
+# Install dependencies needed for native modules
+RUN apk add --no-cache python3 make g++
+
+# Copy package files
+COPY package.json package-lock.json* ./
+
+# Install only production dependencies
+RUN npm ci --only=production && npm cache clean --force
+
+# Copy built application from builder stage
+COPY --from=builder /app/dist ./dist
+COPY --from=builder /app/package.json ./
+
+# Create logs directory with proper permissions
+RUN mkdir -p logs && chmod 777 logs
+
+# Create non-root user but don't switch to it for now
+RUN addgroup -g 1001 -S nodejs
+RUN adduser -S serpentrace -u 1001
+RUN chown -R serpentrace:nodejs /app
+
+# Keep running as root to avoid permission issues with mounted volumes
+# USER serpentrace
+
+# Expose port
+EXPOSE 3000
+
+# Health check
+HEALTHCHECK --interval=30s --timeout=3s --start-period=5s --retries=3 \
+  CMD curl -f http://localhost:3000/health || exit 1
+
+# Production command
+CMD ["npm", "start"]