chore: release SAC 0.5.0

Bump version, document security hardening in README, add github snapshot
push script with URL/login/IP sanitization for public mirror.

README_en.md

@@ -1,4 +1,4 @@
-# Security Alert Center (SAC)
+# Security Alert Center (SAC)
 
 Self-hosted hub for security events from Linux and Windows agents: ingest, correlation, UI, notifications, host management.
 
@@ -13,7 +13,7 @@ Self-hosted hub for security events from Linux and Windows agents: ingest, corre
 | **security-alert-center** | SAC server (Ubuntu 24.04) |
 | [seaca](https://git.kalinamall.ru/PapaTramp/seaca) | Android client |
 
-**Version:** `0.4.11` · **Deploy:** `sudo /opt/sac-deploy.sh`
+**Version:** `0.5.0` · **Deploy:** `sudo /opt/sac-deploy.sh`
 
 ## Features
 
@@ -25,6 +25,7 @@ Self-hosted hub for security events from Linux and Windows agents: ingest, corre
 - **Hosts** — agent status, inventory, agent updates (SSH/WinRM); WinRM RDP: SAC fetches from git, client downloads zip from SAC, runs local `Deploy-LoginMonitor.ps1` (no git on PC)
 - **Mobile** — enrollment, devices, push; Seaca: ack/resolve, qwinsta/logoff via SAC API
 - **Roles** — `admin` / `monitor`
+- **Security (0.5.0)** — SSH host-key verification, SSE via httpOnly cookie, anti-spoof login rate limit, `SAC_SECURITY_ENFORCE`, HMAC API keys
 
 ## Documentation
 
@@ -39,7 +40,7 @@ Self-hosted hub for security events from Linux and Windows agents: ingest, corre
 
 ```bash
 git clone https://git.kalinamall.ru/PapaTramp/security-alert-center.git /opt/security-alert-center
-# deploy/env.native.example -> config/sac-api.env
+# deploy/env.native.example → config/sac-api.env
 cd /opt/security-alert-center/backend && python3 -m venv .venv
 .venv/bin/pip install -r requirements.txt && .venv/bin/alembic upgrade head
 ```