Function dispatch 

pub async fn dispatch(
    state: &AppState,
    ctx: RequestContext,
) -> Result<(Vec<Frame>, ExecutionMetrics), ExecuteError>

Dispatch a query/command/admin operation through the actor with interceptors.

This is the single entry point for all native transport handlers. The caller is responsible only for:

1. Extracting identity from transport-specific auth
2. Building RequestMetadata from transport-specific headers
3. Parsing params from transport-specific wire format
4. Converting the result into transport-specific response format