Recycle bin for deleted knowbys — 30-day restore window

Deleting a knowby is currently immediate and permanent from the user's perspective. There's no way for a customer to recover from an accidental (or malicious) deletion without contacting support to reverse the soft delete. A recent support case showed the impact: a customer deleted a knowby by mistake, and downstream data (Excel export titles) silently degraded because the knowby no longer existed.

Proposed solution
A recycle-bin style holding area:

• Deleted knowbys move to a recycle bin instead of disappearing

• Admins can restore them for up to 30 days

• After 30 days they're permanently deleted (keeps the bin manageable and avoids retaining deleted content indefinitely)

• Optionally: allow an admin to permanently delete from the bin earlier