Initial commit: Windmill Git Sync service

Add containerized service for syncing Windmill workspaces to Git repositories.

Features:
- Flask webhook server for triggering syncs from Windmill
- wmill CLI integration for pulling workspace content
- Automated Git commits and push to remote repository
- Network-isolated (only accessible within Docker network)
- Designed to integrate with existing Windmill docker-compose files

Key components:
- Docker container with Python 3.11, wmill CLI, Git, and Flask
- Sync engine with error handling and logging
- External volume support for persistent workspace data
- Comprehensive documentation (README.md and CLAUDE.md)

README.md

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+# Windmill Git Sync
+
+A containerized service for syncing Windmill workspaces to Git repositories via webhook triggers.
+
+## Overview
+
+This service provides automated backup of Windmill workspaces to Git. It runs a lightweight Flask web server that responds to webhook requests from Windmill, syncing the workspace content using the `wmill` CLI and pushing changes to a remote Git repository.
+
+## Features
+
+- **Webhook-triggered sync**: Windmill can trigger backups via HTTP POST requests
+- **Dockerized**: Runs as a container in the same network as Windmill
+- **Git integration**: Automatic commits and pushes to remote repository
+- **Authentication**: Supports Personal Access Token (PAT) authentication for Git
+- **Health checks**: Built-in health endpoint for monitoring
+
+## Quick Start
+
+This service is designed to be added to your existing Windmill docker-compose file.
+
+1. Copy the example environment file:
+   ```bash
+   cp .env.example .env
+   ```
+
+2. Edit `.env` with your configuration:
+   - Set `WINDMILL_TOKEN` to your Windmill API token
+   - Set `GIT_REMOTE_URL` to your Git repository URL
+   - Set `GIT_TOKEN` to your Git Personal Access Token
+   - Set `WORKSPACE_VOLUME` to an external Docker volume name
+
+3. Create the external volume:
+   ```bash
+   docker volume create windmill-workspace-data
+   ```
+
+4. Add the `windmill-git-sync` service block from `docker-compose.yml` to your existing Windmill docker-compose file.
+
+5. Build and start the service:
+   ```bash
+   docker-compose up -d windmill-git-sync
+   ```
+
+6. Trigger a sync from Windmill (see Integration section below) or test from another container:
+   ```bash
+   docker-compose exec windmill_server curl -X POST http://windmill-git-sync:8080/sync
+   ```
+
+## Configuration
+
+All configuration is done via environment variables in `.env`:
+
+| Variable | Required | Description |
+|----------|----------|-------------|
+| `WINDMILL_BASE_URL` | Yes | URL of Windmill instance (e.g., `http://windmill:8000`) |
+| `WINDMILL_TOKEN` | Yes | Windmill API token for authentication |
+| `WINDMILL_WORKSPACE` | No | Workspace name (default: `default`) |
+| `WORKSPACE_VOLUME` | Yes | External Docker volume name for workspace data |
+| `GIT_REMOTE_URL` | Yes | HTTPS Git repository URL |
+| `GIT_TOKEN` | Yes | Git Personal Access Token |
+| `GIT_BRANCH` | No | Branch to push to (default: `main`) |
+| `GIT_USER_NAME` | No | Git commit author name |
+| `GIT_USER_EMAIL` | No | Git commit author email |
+
+## API Endpoints
+
+This service is only accessible within the Docker network (not exposed to the host).
+
+- `GET /health` - Health check endpoint
+- `POST /sync` - Trigger a workspace sync to Git
+
+## Integration with Windmill
+
+Create a scheduled flow or script in Windmill to trigger backups:
+
+```typescript
+export async function main() {
+  const response = await fetch('http://windmill-git-sync:8080/sync', {
+    method: 'POST'
+  });
+  return await response.json();
+}
+```
+
+## Development
+
+See [CLAUDE.md](CLAUDE.md) for development instructions and architecture details.
+
+## License
+
+MIT