fix: event terminate-session 500 on rdp.login.success (0.3.7)

Use extract_event_actor_user instead of missing ORM field; map WinRM/SSH errors to HTTP 400.

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/src/version.ts

@@ -1,4 +1,4 @@
 /** Fallback до загрузки /health; при релизе держите в sync с backend/app/version.py */
 export const APP_NAME = "Security Alert Center";
-export const APP_VERSION = "0.3.6";
+export const APP_VERSION = "0.3.7";
 export const APP_VERSION_LABEL = `${APP_NAME} v.${APP_VERSION}`;