feat(move-file): handle empty source project after move

[LayZeeDK]

Summary

When the move-file generator moves the last exported file from a source project, the source project's index file can become empty or have only an empty export. The generator should handle this case by ensuring the source project has a valid TypeScript module even when empty.

Current Behavior

After moving the last/only exported file from a source project:

• The source project's index.ts may be left empty or invalid
• This can cause TypeScript compilation errors
• Build tools may fail on the now-empty project

Proposed Behavior

When a move operation leaves the source project with no remaining exports:

1. Write export {} to the source project's entry point (index.ts)
2. This creates a valid TypeScript module even when empty
3. Prevents compilation/build errors

Example

Before move:

// lib-a/src/index.ts
export * from './lib/util';

After moving lib/util.ts to lib-b:

// lib-a/src/index.ts
export {};

Context

Discovered during implementation of e2e test scenarios in #333. The MOVE-SMALL scenario moves a file between libraries and exposes this edge case.

Acceptance Criteria

• Generator detects when source project has no remaining exports
• Generator writes export {} to source project's entry point
• Source project remains valid TypeScript module
• Builds succeed for both source and target projects
• Add test case for this scenario

Related Issues

• Parent: Adopt new end-to-end test plan #319 - Adopt new end-to-end test plan
• Discovered in: test(e2e): implement basic move scenarios #333 - Implement basic move scenarios