docs(cli): link runtime configuration from add help

[wsj040303]

The openarc add --help runtime configuration option describes the JSON input but does not tell users where the advanced OpenVINO properties are documented.

Add the configuration reference URL to the existing option help, retaining the JSON example. A CLI test verifies the link is visible at both 80- and 160-column terminal widths.

Fixes #176.

Validation:

• Actual CLI help reproduced the missing link before the change.
• The two new help cases failed before the change and pass after it.
• tests/unit/test_cli_runtime_config_help_unit.py and the related CLI/YAML/context tests: 49 passed in 0.22s.
• The linked published configuration page and its runtime_config anchor were checked.
• git diff --check: passed.

This change only updates help text; no model execution is needed. The full OpenVINO/model integration suite was not run.