Secure Share Links for Outputs

Outputs now use secure, token-based share links instead of exposing raw IDs. Create multiple links per output, set expiration dates, track view counts, and revoke access anytime.

• ›Token-based share URLs -- output IDs are never exposed publicly
• ›Expiration options: no expiry, 1 day, 7 days, or 30 days
• ›View count tracking shows how many times each shared link has been accessed
• ›Revoke any share link instantly to cut off access
• ›New share modal with full link management -- create, copy, and revoke from one place
• ›Expired links return a clear "link has expired" message