When debug capture is requested, the trace is now also appended to the
step's notes textarea with a clear --- SMTP debug trace ... --- header
and timestamp. This means:
- The technician can edit/trim the trace before finishing the session.
- It flows naturally into the Markdown + HTML report via the existing
notes-in-report rendering — no special-casing needed.
- Pre-existing notes are preserved (appended to, not overwritten).
- Status is preserved.
- The collapsible details block on the step card still shows the raw
capture for quick reference.