refactor: Reorganize repository structure for better maintainability

Major structural improvements:
- Created organized directory structure with logical separation
- bin/ directory for legacy scripts (poc.sh, prod.sh)
- config/ directory for configuration templates
- tests/ directory for test framework
- docs/ directory for documentation (ADRs)

Enhanced build system:
- Comprehensive Makefile with 20+ commands for development workflow
- Full CI/CD pipeline support (test, lint, security-check)
- Vendor integration testing for git vendor inclusion scenarios
- Development environment setup and configuration management

Updated test framework:
- Smart path resolution for both organized and vendored structures
- Improved vendor compatibility testing
- Enhanced error handling and timeout protection

Documentation updates:
- Updated README with new directory structure
- Comprehensive command reference and usage examples
- Clear vendor integration guidelines
- Architecture Decision Record for Node.js version management

Files moved:
- poc.sh, prod.sh → bin/ (legacy scripts)
- bitwarden-config.conf.sample → config/
- test-secrets-manager.sh → tests/
- ADR-Node.md → docs/

All path references updated to maintain full functionality.
This reorganization improves maintainability while preserving
compatibility for git vendor inclusion scenarios.

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

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

README.md

@@ -22,7 +22,7 @@ A comprehensive bash script solution for managing secrets at TSYS using the Bitw
 
 2. **Create Configuration**:
    ```bash
-   cp bitwarden-config.conf.sample bitwarden-config.conf
+   cp config/bitwarden-config.conf.sample bitwarden-config.conf
    # Edit bitwarden-config.conf with your actual Bitwarden credentials
    ```
 
@@ -43,7 +43,7 @@ A comprehensive bash script solution for managing secrets at TSYS using the Bitw
 
 ## Configuration
 
-Create a `bitwarden-config.conf` file based on the provided sample:
+Create a `bitwarden-config.conf` file based on the provided sample in the `config/` directory:
 
 ```bash
 # Bitwarden server URL
@@ -146,21 +146,122 @@ All operations are logged to `/tmp/secrets-manager.sh.log` for debugging and aud
 
 ## Legacy Scripts
 
-This repository also contains previous implementations:
+## Repository Structure
 
-- **`poc.sh`** - Original proof of concept
-- **`prod.sh`** - ChatGPT-assisted production attempt
+```
+KNELSecretsManager/
+├── secrets-manager.sh           # Main secrets management script
+├── README.md                    # This documentation
+├── LICENSE                      # License information
+├── Makefile                     # Build and test automation
+├── .gitignore                   # Git ignore rules
+├── bin/                        # Legacy scripts and utilities
+│   ├── poc.sh                  # Original proof of concept
+│   └── prod.sh                 # ChatGPT-assisted production attempt
+├── config/                     # Configuration templates
+│   └── bitwarden-config.conf.sample  # Sample configuration
+├── tests/                      # Test suite
+│   └── test-secrets-manager.sh # Comprehensive test framework
+└── docs/                       # Documentation
+    └── ADR-Node.md             # Architecture Decision Records
+```
 
-The new `secrets-manager.sh` combines the best features of both while adding robust error handling, installation management, and improved security.
+The main `secrets-manager.sh` script combines the best features of the legacy implementations while adding robust error handling, installation management, and improved security.
+
+## Testing
+
+This project includes a comprehensive test suite designed to work both standalone and when vendored into shell scripting frameworks.
+
+### Running Tests
+
+```bash
+# Run all tests
+./tests/test-secrets-manager.sh run
+
+# Run tests in CI mode (no colors)
+./tests/test-secrets-manager.sh --ci run
+
+# Using Make (recommended)
+make test          # Run all tests
+make test-ci       # Run in CI mode
+make lint          # Run shellcheck
+make all           # Run deps, lint, and tests
+```
+
+### Test Coverage
+
+The test suite covers:
+- Script existence and permissions
+- Command-line argument parsing
+- Help and version output
+- Error handling and exit codes
+- Configuration file validation
+- Bitwarden CLI dependency checks
+- Performance and startup time
+- Vendor integration compatibility
+
+### Vendor Integration Testing
+
+When this project is vendored into other shell scripting frameworks:
+
+```bash
+# Test as vendored dependency
+make vendor-test
+
+# Or manually
+mkdir /tmp/vendor-test
+cp secrets-manager.sh tests/test-secrets-manager.sh config/bitwarden-config.conf.sample /tmp/vendor-test/
+cd /tmp/vendor-test && ./test-secrets-manager.sh --ci run
+```
+
+### Development Testing
+
+```bash
+# Setup development environment
+make dev-setup
+
+# Run tests with development config
+make dev-test
+```
+
+## Architecture Decision Records
+
+This project includes ADRs for key architectural decisions:
+
+- **ADR-001**: [Node.js Version Management Strategy](docs/ADR-Node.md) - Analysis of MISE vs system packages for Node.js version management
 
 ## Contributing
 
 When contributing to this project:
 
-1. Test all changes thoroughly
-2. Update documentation as needed
-3. Follow existing code style and conventions
-4. Ensure security best practices are maintained
+1. **Test all changes thoroughly**:
+   ```bash
+   make ci  # Run full CI pipeline
+   ```
+
+2. **Update documentation as needed**
+3. **Follow existing code style and conventions**
+4. **Run security checks**:
+   ```bash
+   make security-check
+   ```
+
+5. **Ensure compatibility with vendor integration**:
+   ```bash
+   make vendor-test
+   ```
+
+## Development Commands
+
+```bash
+make help           # Show all available commands
+make install        # Install dependencies
+make dev-setup      # Setup development environment
+make lint           # Run shellcheck
+make security-check # Basic security validation
+make clean          # Clean temporary files
+make docs           # Generate documentation
+```
 
 ## License