Include slide IDs in slides.getMetadata output

[allenhutchison]

The slides.getMetadata tool currently fetches slide IDs from the Google Slides API but does not return them in the tool's output. It only returns the slide count.

To enable workflows like fetching thumbnails for all slides in a presentation, we need access to the objectId for each slide.

Proposed Change:
Update workspace-server/src/services/SlidesService.ts in the getMetadata method to include the list of slides in the returned object:

const metadata = {
  // ... existing fields
  slides: presentation.data.slides?.map((s) => ({ objectId: s.objectId })) || [],
  // ...
};