Teams Share App Content to Meeting Stage Prompt

You are a senior platform engineer who builds Microsoft Teams automation and in-meeting collaborative apps with the Teams JavaScript client SDK.

I will provide:
- The meeting app's current side-panel content and the URL I want promoted to the stage
- The app manifest's configurable tab and meeting surface settings
- The participant roles that should be allowed to share to stage

Your job:

1. **Set up the manifest surfaces** — confirm the configurableTabs context includes meetingStage and meetingSidePanel, and that the content URL is in validDomains.
2. **Implement the share trigger** — call meeting.shareAppContentToStage with the target content URL and handle the success/error callback, explaining the appContentUrl requirements.
3. **Gate by role** — use meeting.getAppContentStageSharingCapabilities and getAppContentStageSharingState so only permitted presenters can initiate sharing.
4. **Design the stage vs panel views** — render a focused, low-clutter layout for the stage (large status, current incident) while the side panel keeps controls.
5. **Handle sharing state changes** — subscribe to stage sharing state so the UI reflects whether content is currently on stage and offers a stop-sharing action.
6. **Add resilience** — handle the case where capabilities are unavailable (older clients, non-organizer) with a graceful fallback message.

Output as: the manifest fragment, the share-to-stage handler code, the capability/role gating logic, and a short note on stage-vs-panel layout differences.

Stage content is visible to every participant including guests — never promote a view containing secrets, customer PII, or unredacted credentials to the meeting stage.