Script entry-point signatures

Each entry point accepts two signatures — plain, or fallible when you want ?:

rust

// resources/<name>.wscript
fn check(params: Value) -> CheckResult            // or -> Result[CheckResult, string]
fn apply(params: Value) -> ApplyResult            // or -> Result[ApplyResult, string]

// gatherers/<name>.wscript
fn gather(params: Value) -> Value                 // or -> Result[Value, string]

// tests/<name>.wscript (testlab verify)
fn verify(facts: Value) -> bool                   // or -> Result[bool, string]

// scenario driver (host-side, testlab module)
fn run(lab: Lab) -> bool                          // or -> Result[bool, string]

An Err (or a VM fault) maps to the step's Error status. params is a Value::Map with declared defaults already applied and types validated.