feat: Add SMTP settings and collapsible email configuration UI

- Add SMTP fields to TicketEmailSettings model (host, port, TLS/SSL, credentials, from email/name)
- Update serializers with SMTP fields and is_smtp_configured flag
- Add TicketEmailTestSmtpView for testing SMTP connections
- Update frontend API types and hooks for SMTP settings
- Add collapsible IMAP and SMTP configuration sections with "Configured" badges
- Fix TypeScript errors in mockData.ts (missing required fields, type mismatches)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

frontend/src/types.ts

@@ -233,6 +233,9 @@ export interface Ticket {
   updatedAt: string; // Date string
   resolvedAt?: string; // Date string
   comments?: TicketComment[]; // Nested comments
+  // External sender info (for tickets from non-registered users via email)
+  externalEmail?: string;
+  externalName?: string;
 }
 
 export interface TicketTemplate {
@@ -341,4 +344,52 @@ export interface PluginInstallation {
   hasUpdate: boolean;
   rating?: number;
   review?: string;
+  scheduledTaskId?: string;
+}
+
+// --- Email Template Types ---
+
+export type EmailTemplateScope = 'BUSINESS' | 'PLATFORM';
+
+export type EmailTemplateCategory =
+  | 'APPOINTMENT'
+  | 'REMINDER'
+  | 'CONFIRMATION'
+  | 'MARKETING'
+  | 'NOTIFICATION'
+  | 'REPORT'
+  | 'OTHER';
+
+export interface EmailTemplate {
+  id: string;
+  name: string;
+  description: string;
+  subject: string;
+  htmlContent: string;
+  textContent: string;
+  scope: EmailTemplateScope;
+  isDefault: boolean;
+  category: EmailTemplateCategory;
+  previewContext?: Record<string, any>;
+  createdBy?: number;
+  createdByName?: string;
+  createdAt: string;
+  updatedAt: string;
+}
+
+export interface EmailTemplatePreview {
+  subject: string;
+  htmlContent: string;
+  textContent: string;
+  forceFooter: boolean;
+}
+
+export interface EmailTemplateVariable {
+  code: string;
+  description: string;
+}
+
+export interface EmailTemplateVariableGroup {
+  category: string;
+  items: EmailTemplateVariable[];
 }