Add MIT License and Docker build validation script

- Add MIT License with William Ballou as copyright holder
- Create scripts/validate_docker_build.sh for testing Docker builds independently
- Update documentation to reflect API-based secret configuration model
- Refactor sync.py to accept config via function parameters instead of env vars
- Update server.py to parse JSON payloads and validate required fields
- Improve security by removing secrets from environment variables

.env.example

@@ -1,14 +1,16 @@
-# Windmill Configuration
-WINDMILL_BASE_URL=http://windmill_server:8000
-WINDMILL_TOKEN=your-windmill-token-here
-WINDMILL_WORKSPACE=home
+# ===================================================
+# Add these lines to your existing Windmill .env file
+# ===================================================
+#
+# This service is designed to integrate with your existing Windmill
+# docker-compose setup. The configuration below should be added to
+# the same .env file that contains your existing Windmill settings
+# (like WINDMILL_DATA_PATH).
+#
+# Required: Your existing .env should already have:
+#   WINDMILL_DATA_PATH=/path/to/windmill/data
+#
+# ===================================================
 
-# Workspace Volume (external Docker volume name)
-WORKSPACE_VOLUME=windmill-workspace-data
-
-# Git Configuration
-GIT_REMOTE_URL=https://github.com/username/repo.git
-GIT_TOKEN=your-github-pat-here
-GIT_BRANCH=main
-GIT_USER_NAME=Windmill Git Sync
-GIT_USER_EMAIL=windmill@example.com
+# windmill-git-sync Service Configuration
+WINDMILL_BASE_URL=http://windmill_server:8000