feat: enhance Docker build process and deployment options

- Add multi-platform Docker build support with docker-bake.hcl
- Update Dockerfile with improved production build configurations
- Enhance Makefile with streamlined deployment targets for local, dev, and prod
- Improve buildx-helper.sh script for better cross-platform builds
- Fix production build security validations for JWT_SECRET and SESSION_SECRET
- Add comprehensive deployment documentation and environment setup guides

These changes enable efficient multi-platform image creation and provide
clear deployment workflows for different environments.

docker/Dockerfile

@@ -6,7 +6,7 @@
 FROM oven/bun:alpine AS builder
 
 # Install system dependencies for native modules
-RUN apk add --no-cache python3 make g++ gettext
+RUN apk add --no-cache python3 make gcc g++ musl-dev gettext
 
 # Create non-root user for security
 RUN addgroup -g 1001 -S nodeuser && adduser -S nodeuser -u 1001 -G nodeuser
@@ -39,6 +39,7 @@ ARG VITE_COUCHDB_PASSWORD=change-this-secure-password
 
 # Authentication Configuration
 ARG JWT_SECRET=your-super-secret-jwt-key-change-in-production
+ARG SESSION_SECRET=your-super-secret-session-key-change-in-production
 
 # Email Configuration (Optional)
 ARG VITE_MAILGUN_API_KEY=""