Epistemic stamp via top-level `lambda` declaration

Primitives used: persona · flow · lambda

// `lambda` is NOT λ-calculus abstraction; it is the epistemic-metadata
// primitive that carries (ontology, certainty, temporal_frame,
// provenance, derivation). Production flows in regulated domains
// declare a lambda alongside their inference flow so the audit trail
// records the derivation context for every produced value.

persona Diagnoser {
    domain: ["clinical-inference"]
    tone: analytical
    confidence_threshold: 0.85
    cite_sources: true
}

// The lambda declares the epistemic stamp the runtime applies to
// outputs of the matching flow / step under the runtime's binding.
lambda DiagnosisCandidate {
    ontology:       "ClinicalInference"
    certainty:      0.85
    temporal_frame: "2025-01-01" "2026-12-31"
    provenance:     "EHR cohort 2024 + clinical guideline ICD-11"
    derivation:     inferred
}

type SymptomList       { items: String }
type ClusteredSymptoms { items: String }
type Diagnosis         { label: String }

flow Diagnose(symptoms: SymptomList) -> Diagnosis {
    step Cluster {
        given: symptoms
        ask: "Cluster the symptoms by aetiology."
        output: ClusteredSymptoms
    }
    step Decide {
        given: Cluster.output
        ask: "Emit the diagnosis from the clustered symptoms."
        output: Diagnosis
    }
    return Decide.output
}