feat: implement full scrip action engine with real executors

- SendEmail: real nodemailer transport with SMTP config, dynamic recipient resolution
  (static + ticket creator/owner lookup), Handlebars template support
- Webhook: HTTP POST/any method with configurable headers and JSON body
- FetchMetadata: external HTTP fetch, Handlebars URL/body templating,
  auto-adds result as comment/correspondence on ticket
- RunScript: arbitrary async JS execution with helpers (addComment,
  createTransaction, updateTicket, touchTicket), ticket context, and
  Drizzle ORM access
- SetCustomField: lookup by id/key/name, clear+insert value, record
  CustomFieldChange transaction
- CreateTransaction: insert arbitrary transaction record
- Add OnCustomFieldChange condition
- Pass condition_config to evaluator in engine

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/scrip/templates.ts

@@ -17,7 +17,7 @@ export class TemplateRenderer {
 
 export interface TemplateContext {
   ticket: {
-    id: string;
+    id: number;
     subject: string;
     status: string;
     queue_id: string;