/**
 * VariableEnvelope — Structured variable tracking with provenance.
 *
 * Replaces ad-hoc `Record<string, string>` variable bags with a
 * structured, auditable format. Every variable carries metadata about
 * where it came from, when it was resolved, and its content hash for
 * cache invalidation.
 *
 * Canonical field names: `values` and `provenance`.
 * The storage layer (Content Lake) may adapt these to different names
 * on serialization (e.g., `vars`/`meta`), but the domain model always
 * uses the canonical names defined here.
 *
 * @see docs/design-docs/architecture-overhaul/domain-model.md (canonical)
 */
export {};
