fix: auto-fix findings from no-mistakes review

- Remove duplicate  import
- Fix  →  in create ticket
- Fix  →  in ticket detail
- Add note field to TicketUpdate schema and handle note-only updates in backend
- Update frontend submitNote() to use PATCH endpoint

app/templates/tickets/new.html

@@ -244,7 +244,7 @@
                     const payload = {
                         description: this.form.description,
                         priority: this.form.priority || null,
-                        reporter: this.form.reporter || this.user.full_name,
+                        reporter: this.form.reporter || app().user.full_name,
                         reported_via: this.form.reported_via || 'walk-in',
                         category_id: this.form.category_id ? parseInt(this.form.category_id) : (this.form.category_main ? parseInt(this.form.category_main) : null),
                     };