fix: add __main__ guard to adguardhome CLI module (#438)

`cli_anything/adguardhome/adguardhome_cli.py` defined `main()` but never
invoked it under an `if __name__ == "__main__":` guard, so running the module
with `python -m cli_anything.adguardhome.adguardhome_cli` exited 0 without any
output.

That is the exact module path the `_resolve_cli()` helper in
`tests/test_full_e2e.py` falls back to when the console script is not on PATH,
so five of the seven subprocess tests failed on a plain checkout while two
others — which asserted only the exit code — stayed green.

- add the guard to `adguardhome_cli.py`
- assert command-specific stdout in `test_rewrite_help` and `test_blocking_help`,
  matching their sibling tests, so the pair can detect an inert entry point
- bump the harness version to 1.0.1 in `setup.py` and `registry.json`

Fixes #436


Claude-Session: https://claude.ai/code/session_01ChPxA9ksnNqr83nLbfMhwu

Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>