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

src/scrip/conditions.ts

@@ -18,6 +18,7 @@ export interface ConditionConfig {
   new_value?: unknown;
   value?: unknown;
   link_type?: unknown;
+  breach_type?: unknown;
 }
 
 export interface ConditionEvaluator {
@@ -97,6 +98,27 @@ export class OnLinkCreate implements ConditionEvaluator {
   }
 }
 
+export class OnSlaBreach implements ConditionEvaluator {
+  evaluate(ticket: Ticket, _transactions: Transaction[], _context?: ConditionEvaluateContext, config?: ConditionConfig): boolean {
+    const breachType = config?.breach_type ?? 'any';
+
+    // Check if ticket has sla_breached set
+    const breached = (ticket as any).sla_breached as string | null;
+
+    if (breachType === 'any') {
+      return breached === 'response' || breached === 'resolution' || breached === 'both';
+    }
+    if (breachType === 'response') {
+      return breached === 'response' || breached === 'both';
+    }
+    if (breachType === 'resolution') {
+      return breached === 'resolution' || breached === 'both';
+    }
+
+    return false;
+  }
+}
+
 export class OnOverdue implements ConditionEvaluator {
   evaluate(_ticket: Ticket, _transactions: Transaction[], context?: ConditionEvaluateContext, config?: ConditionConfig): boolean {
     const fieldKey = config?.field_key ?? config?.field_id ?? config?.field;
@@ -130,6 +152,7 @@ const conditionRegistry: Record<string, ConditionEvaluator> = {
   OnCustomFieldChange: new OnCustomFieldChange(),
   OnLinkCreate: new OnLinkCreate(),
   OnOverdue: new OnOverdue(),
+  OnSlaBreach: new OnSlaBreach(),
 };
 
 export function getConditionEvaluator(type: string): ConditionEvaluator | null {