Fix CommonJS rewrites in shorthand destructuring defaults

[Copilot]

Imported and exported identifiers used inside shorthand destructuring default initializers were emitted unchanged in CommonJS output, causing runtime ReferenceErrors.

• Identifier reference detection

  • Treat ShorthandPropertyAssignment.ObjectAssignmentInitializer as an expression reference position.
  • This allows existing CommonJS substitution logic to rewrite imported/exported identifiers there.

• Regression coverage

  • Added a compiler emit test covering both imported and exported identifiers in shorthand destructuring defaults.

import { imported } from "./b";
export const exported = 2;
let a, b;
({ a = imported, b = exported } = {});

now emits:

({ a = b_1.imported, b = exports.exported } = {});

[Copilot]

Pull request overview

Fixes CommonJS emit rewriting for imported/exported identifiers used in shorthand destructuring default initializers (e.g. ({ a = imported } = {})), preventing runtime ReferenceErrors by ensuring name substitution runs in that expression position.

Changes:

• Update identifier reference detection to treat ShorthandPropertyAssignment.ObjectAssignmentInitializer as an expression reference position.
• Add a new compiler emit regression test covering both imported and exported identifiers in shorthand destructuring defaults.
• Add the corresponding reference baseline verifying emitted CommonJS output rewrites to require(...)/exports.* references.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
internal/transformers/utilities.go	Extends IsIdentifierReference so identifier substitution applies within shorthand destructuring default initializers.
testdata/tests/cases/compiler/commonjsShorthandDestructuringDefaultImportExport.ts	Adds a targeted compiler test for shorthand destructuring defaults referencing imports/exports under CommonJS.
testdata/baselines/reference/compiler/commonjsShorthandDestructuringDefaultImportExport.js	Adds the reference baseline asserting correct rewritten CommonJS emit.

[RyanCavanaugh]

Very disturbing to not have Strada test for this!