feat: watcher/CC system, SLA engine, and rich text comments

- Watcher system: ticket_watchers table, watch/unwatch endpoints,
  notifications to watchers on comments and updates, watcher/cc
  recipient sources in SendEmail scrip action, watch toggle and
  watcher avatars in ticket detail UI
- SLA engine: sla_policies table, SLA deadline columns on tickets,
  CRUD routes, OnSlaBreach scrip condition, scheduler SLA calculation,
  deadlines set on create/reply, cleared on resolve, SLA indicators
  on ticket list and detail, SLA Policies tab in admin
- Rich text: marked-based markdown rendering with XSS safety,
  Write/Preview toggle in comment composer, styled prose output

web/src/app/page.tsx

@@ -1094,6 +1094,23 @@ function TicketWorkbenchContent() {
                             style={{ backgroundColor: STATUS_META[ticket.status]?.color ?? "#71717a" }}
                             title={statusLabel(ticket.status)}
                           />
+                          {(ticket as any).sla_breached && (
+                            <span
+                              className="h-2 w-2 rounded-full shrink-0 bg-red-500"
+                              title={`SLA breached: ${(ticket as any).sla_breached}`}
+                            />
+                          )}
+                          {!(ticket as any).sla_breached && (ticket as any).sla_resolution_deadline && (
+                            <span
+                              className={cn(
+                                "h-2 w-2 rounded-full shrink-0",
+                                new Date((ticket as any).sla_resolution_deadline) < new Date(Date.now() + 60 * 60 * 1000)
+                                  ? "bg-amber-500"
+                                  : "bg-emerald-500"
+                              )}
+                              title={`SLA due ${formatDistanceToNow(new Date((ticket as any).sla_resolution_deadline), { addSuffix: true })}`}
+                            />
+                          )}
                         </div>
                         {row1Fields.map((col) => {
                           const cellStyle = {