[AGENT] Show archive actions for personal meeting owners

[BASIC-BIT]

[AGENT]

Summary

Personal meeting owners should be able to archive and unarchive their own meetings from the portal.

Current behavior

• Backend metadata management allows the owner of a personal meeting to manage the meeting.
• The frontend meeting detail header only renders the Archive/Unarchive button when the selected server can be managed.
• Personal meetings opened from My Meetings can therefore hide the archive action even when the owner should be allowed to archive them.

Expected behavior

The archive action should be visible for personal meeting owners and should still use the existing confirmation modal.

Acceptance criteria

1. Personal meeting owners see Archive/Unarchive in meeting detail.
2. The existing archive confirmation modal appears before changing archive state.
3. Server-owned meetings continue requiring the appropriate server management permission.
4. Tests cover personal owner visibility and non-owner/non-manager restrictions where practical.