Implement main-thread Camino sessions and synchronous CRDT editing

src/capability-model/types.ts

@@ -65,6 +65,7 @@ export type ValueType =
   | { kind: "scalar"; name: ScalarValueTypeName }
   | { kind: "message"; descriptorId: string }
   | { kind: "record"; fields: Record<string, ValueType> }
+  | { kind: "variant"; id: string; cases: Record<string, { id: string; value: ValueType }> }
   | { kind: "object-ref"; expectation: ObjectExpectation }
   | { kind: "optional"; value: ValueType }
   | { kind: "list"; value: ValueType }
@@ -270,6 +271,8 @@ export interface DependencyPort {
 }
 
 interface PackageExportBase {
+  /** Returns this declared birth, with unchanged operation input as its initializer. */
+  preparation?: { port: DependencyPortId; key: string };
   /** Required authoritative snapshot export in this package. */
   acceptanceExportId?: PackageExportId;
   execution?: ExecutionContract;