ActorRegistry._actor_name() built names via f"{provider}/{model}", which
produced names with multiple slashes when providers included models
containing "/" (e.g. OpenRouter's "anthropic/claude-sonnet-4-20250514").
The resulting name violated the spec pattern ^[a-z0-9_-]+/[a-z0-9_-]+$
and triggered a ValidationError during actor upsert.
Now sanitises both provider and model components by replacing "/" with "-"
and lowercasing, so multi-slash provider models no longer break actor
listing.
Includes 6 Behave BDD regression scenarios (covering zero-provider,
multi-slash, consecutive-slash, leading-slash, and name-validation
cases), Robot Framework integration smoke tests, and ASV benchmarks.
ISSUES CLOSED: #592