Allow Admins to Attach Files When Working Tickets

Allow admin and agent users to attach files — images, PDFs, documents, logs, etc. — to tickets while working them, not only when the ticket is being created by the requester. Attachments should be addable, viewable, and downloadable from the ticket detail view, with visibility controls for internal-only vs. shared with the requester.
What problem does it solve?
Admins frequently need to add supporting files to a ticket during the work, but currently have no way to do so. This forces awkward workarounds — pasting links to external storage, emailing attachments outside the system, or describing what would have been shown — and the information no longer lives with the ticket. Specific scenarios where this gap hurts:

A tech onsite takes a photo of damaged hardware (cracked screen, swollen battery, asset tag) needed for warranty, insurance, or repair-vendor records
Diagnostic output: battery health reports, event log exports, network traces, screenshots from a remote session
Quotes, invoices, or vendor PDFs supporting a hardware or software purchase request
Signed forms attached after the fact (equipment receipt, parent permission, AUP acknowledgment)
Screenshots a user texts or emails to a tech that need to be moved onto the official ticket record
Visual instructions, network diagrams, or configuration guides the tech wants to send the requester
Documentation captured during resolution that future techs will need when the same issue recurs

When this information lives outside the ticket, it disappears. Institutional knowledge is lost, audit trails are incomplete, and the next person to touch a similar ticket starts from scratch.
How would it work?

An "Attach file" button and drag-and-drop area in the ticket detail view, available to admin and agent roles
Visibility toggle on each attachment: Internal only (other agents/admins) or Visible to requester
Configurable file-type allow list and size limit, set by the admin
Inline preview for images and PDFs, download for everything else
Each attachment recorded in the ticket's activity log with user, timestamp, filename, and visibility setting
Attachments included in ticket exports and carried along during ticket merges

Who would benefit?

Admins and technicians documenting their work and capturing evidence during resolution
End users receiving clearer instructions, diagrams, and visual confirmations from techs
Future agents reviewing ticket history to resolve recurring issues faster
Helpdesk managers and compliance staff who need a complete record on each ticket
Vendor, warranty, and insurance processes that require documentation tied to a specific incident

Examples and references
Agent-side file attachment is standard in virtually every mature ticketing platform:

Jira / Jira Service Management — agents attach files freely, with visibility controlled at the comment level
Zendesk — agents attach files to tickets and to internal notes
Freshservice — agent attachments with internal vs. public visibility
ServiceNow — attachments on any record, role-based visibility
Help Scout, HappyFox, Kayako — all support agent-side attachments
Spiceworks — attachments supported from both the requester and tech side

Without parity on this basic capability, admins must work around the limitation in ways that degrade the integrity of the ticket record.