US-1.4: Attach Message to Existing Ticket

[beniza]

As a support agent
I want to attach a new message to an existing ticket
So that I can consolidate follow-up communications

Acceptance Criteria:

• "Attach to Ticket" option on each message
• System suggests candidate tickets based on:
  • Sender match
  • Ticket ID in message
  • Topic/Keyword match
• Search/Select manually if suggestion is wrong
• Message added to ticket activity log

Priority: P1 (Should Have - POC)