Implement main-thread Camino sessions and synchronous CRDT editing

src/execution-world/plan.ts

@@ -142,6 +142,9 @@ export function resolvePlannedOperation(
 /** Bound argument/state codec subset. A parsed type alone does not mean a runtime implements it. */
 function checkValue(type: ValueType, path: string, allowChange = false): void {
   switch (type.kind) {
+    case "variant":
+      for (const [label, entry] of Object.entries(type.cases)) checkValue(entry.value, `${path}.${label}`, allowChange);
+      return;
     case "scalar":
     case "object-ref":
       return;