fix: enrich empty rdp.login.success user from RDG 302 (0.5.15)

RCM 1149 often leaves Param1/Param2 empty through RD Gateway; backfill details.user from matching RDG success within 5 minutes, and still close empty-user sessions on RDG end.

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 = "0.5.14";
+export const APP_VERSION = "0.5.15";
 export const APP_VERSION_LABEL = `${APP_NAME} v.${APP_VERSION}`;