feat: Add GitHub Codespaces support with docker-compose-light

## Summary

Adds full GitHub Codespaces development environment configuration leveraging the new `docker-compose-light.yml` for efficient cloud development.

## Key Features

- **Lightweight Setup**: Uses `docker-compose-light.yml` which removes Redis/nginx for faster startup and lower resource usage
- **Multi-Instance Support**: Each Codespace gets isolated database volumes, perfect for testing multiple branches
- **Auto-Configuration**: Includes VS Code extensions, Python/TypeScript settings, and auto-start script
- **Developer Friendly**: Comprehensive README with SSH, VS Code, and browser connection instructions

## Implementation Details

### Files Added
- `.devcontainer/devcontainer.json` - Main configuration with:
  - Docker-in-Docker support for compose
  - Optimized VS Code extensions for Superset development
  - Smart port forwarding (9001 for frontend, 8088 for API)
  - 4-core/8GB recommended resources

- `.devcontainer/start-superset.sh` - Auto-start script that:
  - Uses unique project names per Codespace
  - Handles Docker daemon startup
  - Shows clear status and credentials

- `.devcontainer/README.md` - Developer guide covering:
  - Multiple connection methods (SSH, VS Code, browser)
  - Port forwarding instructions
  - Cost optimization tips
  - Integration with `claude --yes` workflows

## Benefits

1. **Isolated Development**: No risk to local machine when using `claude --yes`
2. **Resource Efficiency**: Laptop stays cool, Codespaces handles the load
3. **Parallel Testing**: Spin up multiple instances for different features
4. **Quick Pause/Resume**: Auto-stops when idle, resumes in ~30 seconds

## Testing

Push to fork and create a Codespace to test. The environment auto-starts Superset and forwards port 9001 with HTTPS.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

.devcontainer/README.md

@@ -0,0 +1,110 @@
+# Superset GitHub Codespaces Development
+
+This configuration uses `docker-compose-light.yml` for lightweight, multi-instance development in GitHub Codespaces.
+
+## Quick Start
+
+1. **Create a Codespace** from this repo (click "Code" → "Codespaces" → "Create codespace")
+2. **Wait for setup** (~3-5 minutes first time)
+3. **Start Superset**:
+   ```bash
+   docker-compose -p ${CODESPACE_NAME} -f docker-compose-light.yml up
+   ```
+4. **Access Superset** at the forwarded port 9001 URL (auto-opens)
+
+## Connecting to Your Codespace
+
+### VS Code Desktop
+1. Install [GitHub Codespaces extension](https://marketplace.visualstudio.com/items?itemName=GitHub.codespaces)
+2. Open Command Palette (`Cmd/Ctrl+Shift+P`)
+3. Run "Codespaces: Connect to Codespace"
+4. Select your Codespace
+
+### SSH Access
+```bash
+# Install GitHub CLI if needed
+brew install gh  # macOS
+# or visit: https://cli.github.com/
+
+# Login to GitHub
+gh auth login
+
+# List your Codespaces
+gh cs list
+
+# SSH into a Codespace
+gh cs ssh -c <codespace-name>
+
+# Or use the interactive selector
+gh cs ssh
+```
+
+### Web Browser
+- Go to https://github.com/codespaces
+- Click on your Codespace to open in browser
+
+## Running Multiple Instances
+
+Perfect for testing different branches/features simultaneously:
+
+```bash
+# Instance 1 (in Codespace 1)
+docker-compose -p feature1 -f docker-compose-light.yml up
+
+# Instance 2 (in Codespace 2)
+NODE_PORT=9002 docker-compose -p feature2 -f docker-compose-light.yml up
+```
+
+## Why docker-compose-light.yml?
+
+- **Faster startup**: No Redis, nginx, or unnecessary services
+- **Lower resources**: Important for Codespaces quotas
+- **Isolated databases**: Each instance gets its own `superset_light` database
+- **Simple access**: Single port (9001) with frontend proxy to backend
+
+## Port Forwarding & URLs
+
+When Superset starts, Codespaces automatically forwards port 9001:
+- **Public URL**: `https://<codespace-name>-9001.app.github.dev`
+- **Visibility**: Private by default (requires GitHub auth)
+- **Make public**: Click port in "Ports" tab → Change visibility
+
+To forward additional ports:
+```bash
+# From outside the Codespace
+gh cs ports forward 5432:5432 -c <codespace-name>  # PostgreSQL
+gh cs ports forward 8088:8088 -c <codespace-name>  # Backend API
+```
+
+## Tips for Claude Code Usage
+
+When using `claude --yes` in Codespaces:
+- All changes are isolated to your Codespace
+- Database/volumes are separate from your local machine
+- Can safely run destructive commands
+- Easy to delete and recreate if needed
+
+## Credentials
+
+Default login (same as docker setup):
+- Username: `admin`
+- Password: `admin`
+
+## Resource Usage
+
+The light compose typically uses:
+- ~2GB RAM (vs ~4GB for full stack)
+- Minimal CPU when idle
+- ~2GB disk for database + dependencies
+
+## Troubleshooting
+
+If services fail to start:
+```bash
+# Check logs
+docker-compose -f docker-compose-light.yml logs
+
+# Restart fresh
+docker-compose -f docker-compose-light.yml down -v
+docker-compose -f docker-compose-light.yml up
+```