- Add searchMailboxMessages, deleteMailboxMessage, moveToDeletedItems to MsGraphClient
- POST /api/mimecast/mailbox-remediate: search, move, delete actions with permission error handling
- DeliveredAnalysisDialog: Remove from mailbox panel with search → confirm → delete flow
- Shows matching messages in mailbox with checkboxes, received time, read/unread status
- Moves selected to Deleted Items (recoverable) via Graph API
- Surfaces clear permission guidance if Mail.ReadWrite not yet granted