Track A runtime IDs

full-monty exposes stable, host-only runtime IDs for suspendable execution payloads.

• RunProgress::FunctionCall and RunProgress::OsCall include arg_runtime_ids: Vec<RuntimeValueId> and kwarg_runtime_ids: Vec<(RuntimeValueId, RuntimeValueId)>.
• ReplProgress::FunctionCall and ReplProgress::OsCall include the same runtime-ID field types.
• Both progress enums expose runtime_ids() for read-only access to the ID slices without destructuring the enum payload, returning (&[RuntimeValueId], &[(RuntimeValueId, RuntimeValueId)]).

Runtime IDs are opaque host metadata and carry no policy meaning. They remain stable across start() or resume() boundaries and survive dump() or load() round trips for run-progress payloads.