Initial commit: InvenTree Stock Tool v2

A comprehensive barcode scanning application for InvenTree inventory management.

Features:
- Multi-mode operation (Add/Update/Check/Locate stock)
- Smart duplicate prevention when adding stock
- Barcode scanning with automatic part code cleaning
- Real-time server connection monitoring
- Part information display with images
- Debug mode for troubleshooting

Fixes applied:
- Fixed encoding issues with non-ASCII characters in barcodes
- Fixed API response handling for list and dict formats
- Implemented duplicate prevention using PATCH to update existing stock
- Added comprehensive error handling and logging

Includes test suite for verification of all fixes.

.gitignore

@@ -0,0 +1,53 @@
+# Python
+__pycache__/
+*.py[cod]
+*$py.class
+*.so
+.Python
+build/
+develop-eggs/
+dist/
+downloads/
+eggs/
+.eggs/
+lib/
+lib64/
+parts/
+sdist/
+var/
+wheels/
+*.egg-info/
+.installed.cfg
+*.egg
+MANIFEST
+
+# Virtual Environment
+venv/
+env/
+ENV/
+env.bak/
+venv.bak/
+
+# IDE
+.vscode/
+.idea/
+*.swp
+*.swo
+*~
+.DS_Store
+
+# Configuration files (may contain sensitive data)
+*.yaml
+*.yml
+!example_config.yaml
+
+# Logs
+*.log
+
+# Test files (optional - uncomment if you don't want to track tests)
+# test_*.py
+
+# Temporary files
+*.tmp
+*.bak
+*.cache