feat(security): add /elevate command and audit events

src/audit/types.ts

@@ -3,6 +3,8 @@ export type AuditLevel = 'debug' | 'info' | 'warn' | 'error';
 export type AuditEventType =
   // Tool execution
   | 'tool.start' | 'tool.success' | 'tool.error' | 'tool.denied' | 'tool.approval'
+  // Security
+  | 'security.elevation.enabled' | 'security.elevation.disabled' | 'security.elevation.expired'
   // Skills scan
   | 'skills.scan.pass' | 'skills.scan.fail'
   // Skills installer
@@ -134,6 +136,16 @@ export interface SkillsScanEvent {
   issue_codes: string[];
 }
 
+export interface SecurityElevationEvent {
+  session_id: string;
+  channel: string;
+  sender: string;
+  elevation_id: string;
+  until_ms?: number;
+  ttl_ms?: number;
+  reason?: string;
+}
+
 export interface SessionCreateEvent {
   session_id: string;
   frontend: string;