feat : Add safe deletion for specialist Dots

[XENONCYBER]

Summary
Adds a safe way to delete specialist Dots from the workspace.

• Adds a delete action to Dot settings with a confirmation that requires typing the Dot’s name.
• Removes the Dot and its associated workspace data while preserving shared Spaces and pages.
• Blocks deletion when dependencies prevent it and explains what needs attention.
• Refreshes the workspace after deletion and selects a remaining Dot if the deleted one was active.
  Provider-managed transcripts may remain outside the workspace.
  Verification
• Formatter check, lint, typecheck, and production build passed.
• Tests passed.
  Closes Add a way to delete specialist Dots #151