fix(javascript): preserve uncertainty in compound assignment results (#4342)

* fix(javascript): preserve uncertainty in compound assignment results

* fix(javascript): retain callable logical assignment alternatives

* fix(javascript): read prior module export assignment values

* fix: keep mutable module export assignment candidates conservative

* fix: preserve mixed receiver values and wrapped assignment targets

* fix: carry mutable export uncertainty through copied values

src/domain/javascript/javascriptSymbolicValues.ts

@@ -57,6 +57,8 @@ export type SymbolicValue = (
       readonly kind: "namespace";
       readonly bindingId: string;
       readonly environment: SymbolicEnvironment;
+      /** Namespace identity does not establish the mutable root's runtime value. */
+      readonly runtimeValueUnknown?: true;
     }
   | {
       readonly kind: "loader";
@@ -93,6 +95,7 @@ export const symbolicUnion = (
   return unique.length === 1 ? unique[0]! : { kind: "union", values: unique };
 };
 export const symbolicTruth = (value: SymbolicValue): boolean | undefined => {
+  if (value.kind === "namespace" && value.runtimeValueUnknown) return undefined;
   if (value.kind === "union") {
     const choices = value.values.map(symbolicTruth);
     return choices.length > 0 &&