fix: harden SAC security per audit (0.4.15)

Close audit findings: anti-spoof client IP for login rate limit, JWT/CORS
enforce on startup, SSH host-key verification and sudo via stdin, optional
WinRM HTTPS, SSE httpOnly cookie auth, ingest body limit, ILIKE escaping,
and HMAC API key hashing with legacy SHA-256 fallback.

backend/app/version.py

@@ -1,5 +1,5 @@
-"""Единый источник версии SAC (API, health, логи, OpenAPI)."""
+"""Единый источник версии SAC (API, health, логи, OpenAPI)."""
 
 APP_NAME = "Security Alert Center"
-APP_VERSION = "0.4.14"
+APP_VERSION = "0.4.15"
 APP_VERSION_LABEL = f"{APP_NAME} v.{APP_VERSION}"