The test case names in `ufw-docker-service.test.sh` and `ufw-docker.test.sh` were grammatically incorrect and did not clearly describe their purpose.
This commit renames the test cases to be more descriptive and adhere to the Bach testing framework's conventions, using hyphens to improve readability in the test output.
- Add support for IPv6 networks in firewall rule generation and validation.
- Add --docker-subnets [SUBNET1 SUBNET2 ...] option to `ufw-docker install` and `ufw-docker check`.
- When used without arguments, automatically detects and applies all Docker network subnets.
- When given subnet arguments, applies firewall rules only to specified subnets (supports multiple subnets, including non-Docker-managed networks).
- If not specified, falls back to default RFC1918 IPv4 and fd00::/8 IPv6 subnets.
- Improve help output with detailed examples and usage guidance.