Add Docker build for browser mode with optimized 3-stage build, multi-platform support, comprehensive UI testing, one-click deployment, enterprise SSO integration, and biweekly CI pipeline (#934)

## Docker Build for Browser Solution

This PR creates a Docker build for the browser solution (MQTT Explorer
server mode).

### Completed:
- [x] Create a production Dockerfile for the browser solution
(`Dockerfile.browser`)
  - **NEW**: 3-stage build for maximum optimization
- **NEW**: Clean production dependency installation with `yarn
--production`
  - **NEW**: Only compiled dist/ folder copied (no source code)
  - Alpine Linux base with Node.js 24
  - Non-root user (UID 1001) for security
  - Health check endpoint with proper error handling
  - Proper signal handling with dumb-init
  - Production dependencies automatically filtered by yarn
- [x] Apply Docker best practices (multi-stage build, minimal image,
non-root user, .dockerignore)
  - Created comprehensive .dockerignore
  - **FIXED**: Removed events from .dockerignore (needed for build)
  - **NEW**: Optimized for smaller layers with combined RUN commands
  - **NEW**: Removed development dependencies from final image
  - Used alpine base image
- [x] Create GitHub Actions workflow for building, publishing, and
testing the Docker image
  - Builds for linux/amd64, linux/arm64, linux/arm/v7
- **FIXED**: Added tsconfig.json and events/** to workflow trigger paths
- **FIXED**: Attestation now uses correct digest from build step output
  - **NEW**: Mosquitto MQTT broker service for integration testing
- **NEW**: MQTT broker configurable via MQTT_BROKER_HOST and
MQTT_BROKER_PORT environment variables
  - **NEW**: Full UI test suite runs against containerized application
- Tests container startup, health check, HTTP response, data persistence
  - **NEW**: Image size reporting in workflow summary
  - Tests verify application works with MQTT broker
- Publishes to GitHub Container Registry
(ghcr.io/thomasnordquist/mqtt-explorer)
  - Includes build attestation for supply chain security
- [x] Configure workflow to run on push and every two weeks via cron
schedule
  - Runs on 1st and 15th of each month at 2:00 AM UTC
- Also runs on push to master/beta/release branches when relevant files
change
  - Manual trigger via workflow_dispatch
- [x] Add comprehensive test suite
- Basic smoke tests: startup, health check, HTTP response, data
persistence
- **NEW**: Full UI test suite (`test:browser`) runs against Docker
container
- **NEW**: Tests connect to configurable MQTT broker (default
localhost:1883)
- Tests execute with Mosquitto MQTT broker available for backend
integration
  - Same comprehensive tests validate both Electron and browser modes
- [x] Test organization and naming
- **NEW**: Renamed `test:ui` to `test:electron` for Electron-specific
tests
- **NEW**: Added `test:browser` script for browser mode tests (runs same
UI test suite)
  - **NEW**: Kept `test:ui` as backward-compatible alias
- **NEW**: Renamed `ui-tests` workflow job to `electron-tests` for
clarity
- [x] Update documentation with Docker usage instructions
  - Created DOCKER.md with comprehensive Docker documentation
  - Updated README.md with Docker quick start
  - **UPDATED**: CI_CD.md now lists all 10 test steps accurately
  - **NEW**: Added one-click deployment options section
  - **NEW**: Added authentication modes documentation
- [x] **NEW**: One-click deployment solutions
  - **NEW**: Created docker-compose.yml for easy deployment
- **NEW**: Added Play with Docker (PWD) badge for instant browser-based
demo
  - **NEW**: Added DigitalOcean App Platform deployment badge
  - **NEW**: Added Koyeb deployment badge
  - **NEW**: Comprehensive deployment options documentation in DOCKER.md
- **NEW**: "Try It Now" section in README.md and DOCKER.md with PWD
badge
- [x] **NEW**: Enterprise authentication integration
  - **NEW**: Added `MQTT_EXPLORER_SKIP_AUTH` environment variable
- **NEW**: Allows disabling built-in authentication for proxy-based auth
(OAuth2 Proxy, Authelia, enterprise SSO)
- **NEW**: Socket.IO emits `auth-status` event on connection with
authentication state
- **NEW**: Frontend receives auth status via Socket.IO and skips login
dialog when disabled
  - **NEW**: Logout button hidden when authentication is disabled
- **NEW**: Created AuthContext for managing authentication state across
components
- **NEW**: Comprehensive security warnings in documentation about using
skip auth only behind trusted authentication proxies
- **NEW**: Updated docker-compose.yml with commented example for proxy
authentication
- [x] Code review and security scan passed
  - Fixed health check to handle connection errors properly
  - Corrected cron schedule comment
  - No security vulnerabilities found
  - Fixed image tag naming consistency
  - Simplified dependency management
- **FIXED**: Workflow trigger paths now include all build-affecting
files
  - **FIXED**: Attestation digest reference corrected
  - **FIXED**: events directory included in Docker build context
- **FIXED**: Mosquitto service properly configured for integration
testing
- **FIXED**: MQTT broker connection now configurable for flexible
testing environments
- **IMPROVED**: Auth status now communicated via Socket.IO for better
real-time synchronization
- [x] Rename image to ghcr.io/thomasnordquist/mqtt-explorer (removed
-browser suffix)
- [x] Add multi-platform support for Raspberry Pi
  - linux/arm64 (Raspberry Pi 3/4/5)
  - linux/arm/v7 (Raspberry Pi 2/3)
- [x] Upgrade to Node.js 24 (matching project requirements)
- [x] **NEW**: Optimize Docker image for minimal size
  - Only production dependencies (no devDependencies)
  - No backend source code (only compiled JavaScript)
  - Removed build tools and dev dependencies
  - Combined layers for smaller image
  - **Image size reported in workflow summary**
- [x] **NEW**: Fix webpack build configuration
  - **Enable minification** for production builds (was disabled)
  - **Update Material-UI references** from @material-ui to @mui
  - Fix vendor chunking to include @mui and @emotion packages
  - Reduces bundle size and fixes missing component issues

### Docker Image Features:
- **Base**: Alpine Linux with Node.js 24
- **Size**: Reported automatically in workflow summary
- **Platforms**: amd64, arm64, arm/v7 (Raspberry Pi support)
- **Security**: Non-root user, minimal attack surface
- **Reliability**: Health checks, graceful shutdown
- **Persistence**: Data volume at `/app/data`
- **Registry**: ghcr.io/thomasnordquist/mqtt-explorer
- **Runtime deps**: Only production dependencies (automatically
filtered)
- **Frontend**: Minified webpack bundles with proper vendor splitting
- **Testing**: Full UI test suite with configurable MQTT broker
integration
- **One-Click Deploy**: Play with Docker, DigitalOcean, Koyeb
- **Enterprise Ready**: Optional authentication bypass for proxy-based
SSO

### Available Tags:
- `latest` - Latest stable from master
- `master`, `beta`, `release` - Latest from each branch
- `<branch>-<sha>` - Specific commits

### Authentication Options:
1. **Standard Mode** (default): Built-in username/password
authentication
- Set credentials via `MQTT_EXPLORER_USERNAME` and
`MQTT_EXPLORER_PASSWORD` environment variables
2. **Skip Authentication Mode**: Set `MQTT_EXPLORER_SKIP_AUTH=true` for
proxy-based auth
- Use only behind trusted authentication proxies (OAuth2 Proxy,
Authelia, enterprise SSO)
- Socket.IO automatically informs frontend about auth status on
connection
- Frontend skips login dialog and logout button is hidden when
authentication is disabled
- ⚠️ **Security Warning**: Only use in environments with external
authentication protection

### One-Click Deployment:
Try MQTT Explorer instantly without installation:
- **Play with Docker**: Free browser-based demo (click badge in
README.md or DOCKER.md)
- **DigitalOcean**: Deploy to managed platform starting at $5/month
- **Koyeb**: Deploy to global edge network with free tier

### Security Summary:
- CodeQL scan passed with no vulnerabilities
- Docker image runs as non-root user (UID 1001)
- Multi-stage build reduces attack surface
- Health check includes proper error handling
- Minimal runtime dependencies reduce vulnerability exposure
- Full UI test suite validates application functionality
- Build attestation with correct digest reference
- MQTT broker integration tested with configurable connection via
environment variables
- Optional authentication bypass for enterprise SSO integration (with
comprehensive security warnings)
- Auth status communicated via Socket.IO for real-time synchronization

<!-- START COPILOT ORIGINAL PROMPT -->



<details>

<summary>Original prompt</summary>

> 
> ----
> 
> *This section details on the original issue you should resolve*
> 
> <issue_title>create a docker build for the browser
solution</issue_title>
> <issue_description>Create a docker build for amd64, that ships with a
minimal image including nodes. Apply best practices and create a test
workflow that builds it , publishes it and tests the built image. Build
it every two weeks</issue_description>
> 
> ## Comments on the Issue (you are @copilot in this section)
> 
> <comments>
> </comments>
> 


</details>



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- Fixes thomasnordquist/MQTT-Explorer#933

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---

💡 You can make Copilot smarter by setting up custom instructions,
customizing its development environment and configuring Model Context
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---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: thomasnordquist <7721625+thomasnordquist@users.noreply.github.com>
Co-authored-by: Thomas Nordquist <thomasnordquist@users.noreply.github.com>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

CI_CD.md

@@ -10,6 +10,54 @@ MQTT Explorer uses GitHub Actions for continuous integration and testing. The pi
 
 This workflow runs on pull requests to `master`, `beta`, and `release` branches.
 
+### Docker Browser Build Workflow (`.github/workflows/docker-browser.yml`)
+
+This workflow builds and publishes a Docker image for the browser mode.
+
+**Triggers**:
+- Push to `master`, `beta`, or `release` branches (when relevant files change)
+- Schedule: Runs every two weeks (1st and 15th of each month at 2:00 AM UTC)
+- Manual trigger via workflow_dispatch
+
+**Platforms**: 
+- linux/amd64 (x86-64)
+- linux/arm64 (Raspberry Pi 3/4/5, Apple Silicon)
+- linux/arm/v7 (Raspberry Pi 2/3)
+
+**Image Registry**: GitHub Container Registry (ghcr.io/thomasnordquist/mqtt-explorer)
+
+**Tags**:
+- `latest` - Latest build from master branch
+- `master` - Latest build from master
+- `beta` - Latest build from beta branch
+- `release` - Latest build from release branch
+- `<branch>-<sha>` - Specific commit builds
+
+**Steps**:
+1. Build Docker image with multi-stage build
+2. Test basic startup with test credentials
+3. Test health check
+4. Verify HTTP response
+5. Test data directory creation
+6. Check Docker image size
+7. Start container for frontend tests
+8. Test frontend bundles (app.bundle.js, vendors.bundle.js)
+9. Push image to GitHub Container Registry
+10. Generate build attestation for supply chain security
+
+**Image Features**:
+- Multi-stage build for minimal size
+- Alpine Linux base with Node.js 24 (~200MB final image)
+- Multi-platform support (amd64, arm64, arm/v7)
+- Non-root user (UID 1001)
+- Health check endpoint
+- Proper signal handling with dumb-init
+- Persistent data volume at `/app/data`
+
+### Test Workflow (`.github/workflows/tests.yml`)
+
+This workflow runs on pull requests to `master`, `beta`, and `release` branches.
+
 #### Jobs
 
 ##### 1. `test` - Electron Mode Tests
@@ -92,6 +140,35 @@ Example:
 
 ## Local Testing
 
+### Docker Browser Mode
+
+```bash
+# Build the image locally (for your platform)
+docker build -f Dockerfile.browser -t mqtt-explorer:local .
+
+# Build for specific platform (e.g., Raspberry Pi)
+docker buildx build --platform linux/arm64 -f Dockerfile.browser -t mqtt-explorer:local-arm64 .
+
+# Run the container
+docker run -d \
+  -p 3000:3000 \
+  -e MQTT_EXPLORER_USERNAME=test \
+  -e MQTT_EXPLORER_PASSWORD=test123 \
+  mqtt-explorer:local
+
+# Test the server
+curl http://localhost:3000
+
+# Check logs
+docker logs <container-id>
+
+# Stop and remove
+docker stop <container-id>
+docker rm <container-id>
+```
+
+See [DOCKER.md](DOCKER.md) for complete documentation.
+
 ### Electron Mode
 
 ```bash