refactor(drivers): organize backup modules into drivers subfolder

- Move all backup_*.py files to libtisbackup/drivers/ subdirectory
- Move XenAPI.py and copy_vm_xcp.py to drivers/ (driver-specific)
- Create drivers/__init__.py with automatic driver imports
- Update tisbackup.py imports to use new structure
- Add pyvmomi>=8.0.0 as mandatory dependency
- Sync requirements.txt with pyproject.toml dependencies
- Add pylint>=3.0.0 and pytest-cov>=6.0.0 to dev dependencies
- Configure pylint and coverage tools in pyproject.toml
- Add conventional commits guidelines to CLAUDE.md
- Enhance .gitignore with comprehensive patterns for Python, IDEs, testing, and secrets
- Update CLAUDE.md documentation with new structure and tooling

Breaking Changes:
- Drivers must now be imported from libtisbackup.drivers instead of libtisbackup
- All backup driver files relocated to drivers/ subdirectory

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

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

CLAUDE.md

@@ -14,6 +14,8 @@ TISBackup is a server-side backup orchestration system written in Python. It exe
 
 ## Development Commands
 
+**IMPORTANT: Always use `uv run` to execute Python commands in this project.**
+
 ### Dependency Management
 ```bash
 # Install dependencies (uses uv)
@@ -25,37 +27,74 @@ uv lock
 
 ### Linting
 ```bash
-# Run ruff linter
-ruff check .
+# Run ruff linter (fast, primary linter)
+uv run ruff check .
 
 # Auto-fix linting issues
-ruff check --fix .
+uv run ruff check --fix .
+
+# Run pylint (comprehensive static analysis)
+uv run pylint libtisbackup/
+
+# Run pylint on specific file
+uv run pylint libtisbackup/ssh.py
 ```
 
+### Testing
+```bash
+# Run all tests
+uv run pytest
+
+# Run tests for specific module
+uv run pytest tests/test_ssh.py
+
+# Run with verbose output
+uv run pytest -v
+
+# Run tests matching a pattern
+uv run pytest -k "ssh"
+
+# Run with coverage report
+uv run pytest --cov=libtisbackup --cov-report=html --cov-report=term-missing
+
+# Run tests with coverage and show only missing lines
+uv run pytest --cov=libtisbackup --cov-report=term-missing
+
+# Generate HTML coverage report (opens in browser)
+uv run pytest --cov=libtisbackup --cov-report=html
+# Then open htmlcov/index.html
+```
+
+**Coverage reports:**
+- Terminal report: Shows coverage percentage with missing line numbers
+- HTML report: Detailed interactive report in `htmlcov/` directory
+
+See [tests/README.md](tests/README.md) for detailed testing documentation.
+
 ### Running the Application
 
 **Web GUI (development):**
 ```bash
-python3 tisbackup_gui.py
+uv run python tisbackup_gui.py
 # Runs on port 8080, requires config at /etc/tis/tisbackup_gui.ini
 ```
 
 **CLI Commands:**
 ```bash
 # Run backups
-python3 tisbackup.py -c /etc/tis/tisbackup-config.ini backup
+uv run python tisbackup.py -c /etc/tis/tisbackup-config.ini backup
 
 # Run specific backup section
-python3 tisbackup.py -c /etc/tis/tisbackup-config.ini -s section_name backup
+uv run python tisbackup.py -c /etc/tis/tisbackup-config.ini -s section_name backup
 
 # Cleanup old backups
-python3 tisbackup.py -c /etc/tis/tisbackup-config.ini cleanup
+uv run python tisbackup.py -c /etc/tis/tisbackup-config.ini cleanup
 
 # Check backup status (for Nagios)
-python3 tisbackup.py -c /etc/tis/tisbackup-config.ini checknagios
+uv run python tisbackup.py -c /etc/tis/tisbackup-config.ini checknagios
 
 # List available backup drivers
-python3 tisbackup.py listdrivers
+uv run python tisbackup.py listdrivers
 ```
 
 ### Docker
@@ -79,12 +118,22 @@ docker compose up -d
 
 **Backup Driver System:**
 
-All backup logic is implemented via driver classes in [libtisbackup/](libtisbackup/):
+All backup logic is implemented via driver classes in [libtisbackup/drivers/](libtisbackup/drivers/):
 
-- Base class: `backup_generic` in [common.py](libtisbackup/common.py:565) (abstract)
+- Base class: `backup_generic` in [base_driver.py](libtisbackup/base_driver.py) (abstract)
 - Each driver inherits from `backup_generic` and implements specific backup logic
 - Drivers are registered via the `register_driver()` decorator function
 - Configuration is read from INI files using the `read_config()` method
+- All driver implementations are in [libtisbackup/drivers/](libtisbackup/drivers/) subdirectory
+
+**Library Modules:**
+- [base_driver.py](libtisbackup/base_driver.py) - Core `backup_generic` class, driver registry, Nagios states
+- [database.py](libtisbackup/database.py) - `BackupStat` class for SQLite operations
+- [ssh.py](libtisbackup/ssh.py) - SSH utilities with modern key support (Ed25519, ECDSA, RSA)
+- [process.py](libtisbackup/process.py) - Process execution and monitoring utilities
+- [utils.py](libtisbackup/utils.py) - Date/time formatting, number formatting, validation helpers
+- [__init__.py](libtisbackup/__init__.py) - Package exports for backward compatibility
+- [drivers/](libtisbackup/drivers/) - All backup driver implementations
 
 **Available Drivers:**
 - `backup_rsync` / `backup_rsync_ssh` - File-based backups via rsync
@@ -94,8 +143,8 @@ All backup logic is implemented via driver classes in [libtisbackup/](libtisback
 - `backup_oracle` - Oracle database backups
 - `backup_sqlserver` - SQL Server backups
 - `backup_samba4` - Samba4 AD backups
-- `backup_xva` / `backup_xcp_metadata` - XenServer VM backups
-- `backup_vmdk` - VMware VMDK backups
+- `backup_xva` / `backup_xcp_metadata` / `copy_vm_xcp` - XenServer VM backups
+- `backup_vmdk` - VMware VMDK backups (requires pyVmomi)
 - `backup_switch` - Network switch configuration backups
 - `backup_null` - No-op driver for testing
 
@@ -134,15 +183,63 @@ Two-container architecture:
 - Ruff ignores: F401, F403, F405, E402, E701, E722, E741
 - Python 3.13+ required
 
+## Commit Message Guidelines
+
+**IMPORTANT: This project uses [Conventional Commits](https://www.conventionalcommits.org/) format.**
+
+All commit messages must follow this format:
+```
+<type>(<scope>): <description>
+
+[optional body]
+
+[optional footer(s)]
+```
+
+**Types:**
+- `feat`: A new feature
+- `fix`: A bug fix
+- `docs`: Documentation only changes
+- `refactor`: Code change that neither fixes a bug nor adds a feature
+- `test`: Adding missing tests or correcting existing tests
+- `chore`: Changes to build process or auxiliary tools
+- `perf`: Performance improvements
+- `style`: Code style changes (formatting, missing semicolons, etc.)
+
+**Scopes (commonly used):**
+- `auth`: Authentication/authorization changes
+- `security`: Security-related changes
+- `drivers`: Backup driver changes
+- `gui`: Web GUI changes
+- `api`: API changes
+- `readme`: README.md changes
+- `claude`: CLAUDE.md changes
+- `core`: Core library changes
+
+**Examples:**
+- `feat(auth): add pluggable authentication system for Flask routes`
+- `fix(security): replace os.popen/os.system with subprocess`
+- `docs(readme): add comprehensive security and authentication documentation`
+- `refactor(drivers): organize backup modules into drivers subfolder`
+- `chore(deps): add pyvmomi as mandatory dependency`
+
+**Breaking Changes:**
+Add `!` after type/scope for breaking changes:
+- `feat(api)!: remove deprecated endpoint`
+
+**Note:** Always include a scope in parentheses, even for documentation changes.
+
+When Claude Code creates commits, it will automatically follow this format.
+
 ## Important Patterns
 
 **Adding a new backup driver:**
-1. Create `backup_<type>.py` in [libtisbackup/](libtisbackup/)
+1. Create `backup_<type>.py` in [libtisbackup/drivers/](libtisbackup/drivers/)
 2. Inherit from `backup_generic`
 3. Set class attributes: `type`, `required_params`, `optional_params`
 4. Implement abstract methods: `do_backup()`, `cleanup()`, `checknagios()`
 5. Register with `register_driver(backup_<type>)`
-6. Import in [tisbackup.py](tisbackup.py)
+6. Import in [libtisbackup/drivers/__init__.py](libtisbackup/drivers/__init__.py)
 
 **SSH Operations:**
 - Uses paramiko for SSH connections