Add SSRF host validation to maintenance.py send_nightly_email and
scheduler.py send_zombie_alert_email using validate_external_url().
New allow_local_smtp config key permits private-IP SMTP for local
relay setups.
Add sanitize_name() to security_utils and apply it to all log calls
in message_handler, repeater_manager, path_command, solarforecast_command,
command_manager, and discord_bridge_service to prevent log injection.
Move nightly email logic from duplicate scheduler._send_nightly_email()
into the canonical maintenance.py implementation, removing the duplicate.
Update tests to call maintenance.send_nightly_email() directly.
Add validate_external_url allow_private parameter with support for
loopback, RFC1918, CGN, and link-local address ranges.
- Updated the `resolve_path` function in `utils.py` to clarify behavior regarding absolute paths.
- Changed type hints in `discord_bridge_service.py` for better clarity and consistency.
- Removed unused imports and unnecessary comments in various test files to improve code cleanliness and readability.
- Enhanced .gitignore to allow test files in the tests/ directory and committed pytest.ini for test discovery.
- Added checks for missing sections in configuration files, specifically for Admin_ACL and Banned_Users, to prevent errors during bot startup.
- Updated generate_website.py and command_manager.py to handle cases where required sections are absent, returning empty lists instead of raising exceptions.
- Introduced optional dependencies for testing in pyproject.toml, ensuring a smoother development experience.
- Improved localization handling in core.py to default to English when the Localization section is missing, enhancing user experience.