Initial commit: SAP C4C attachment downloader toolkit

- Add Python script for downloading C4C attachments via OData and web scraping
- Add Java wrapper for programmatic access with typed API
- Add DSM upload utility for Synology NAS integration
- Add CLAUDE.md documentation for future development
- Add .gitignore for Python, Java, and sensitive files

.gitignore

@@ -0,0 +1,55 @@
+# Python
+__pycache__/
+*.py[cod]
+*$py.class
+*.so
+.Python
+env/
+venv/
+ENV/
+build/
+develop-eggs/
+dist/
+downloads/
+eggs/
+.eggs/
+lib/
+lib64/
+parts/
+sdist/
+var/
+wheels/
+*.egg-info/
+.installed.cfg
+*.egg
+
+# Java
+*.class
+*.jar
+*.war
+*.ear
+target/
+.classpath
+.project
+.settings/
+
+# IDE
+.vscode/
+.idea/
+*.swp
+*.swo
+*~
+
+# OS
+.DS_Store
+Thumbs.db
+
+# Credentials and sensitive data
+*.env
+.env
+credentials.json
+config.json
+
+# Downloaded files
+downloads/
+*.log