Lock Reply Editing, Allow Note Editing by Owner

Align the platform's behavior with its documentation and legal/retention expectations by locking replies from being edited after they're posted, while allowing notes to be edited — restricted to the original author.
Problem
Documentation states that neither notes nor replies can be edited, but in practice replies on tickets can be edited today. That's the opposite of what's needed:

Replies are part of the customer-facing communication record. For legal, compliance, and retention reasons, they should be immutable once sent. Allowing edits creates risk around audit integrity and dispute resolution.
Notes are where technicians record actions taken, troubleshooting steps, and internal context. Techs regularly need to correct a typo, add a missed detail, or clarify a note shortly after posting. Locking notes forces workarounds (posting a second note to correct the first), which clutters the record and makes the history harder to follow.

Proposed Solution

Lock replies from editing after they're posted, matching the documented behavior and satisfying retention requirements.
Allow notes to be edited, but only by the original author — technicians should not be able to edit each other's notes.
Capture an edit history on notes (original text, edit timestamps, editor) so the audit trail remains intact even when a note is revised.
Update the documentation to reflect the new, correct behavior.

Who Benefits

Technicians — can correct and refine their own notes without cluttering the record.
Compliance and legal — reply history remains immutable and defensible.
Team leads and auditors — clear separation between the customer-facing record (locked) and internal working notes (owner-editable, with history).