feat: initial VPS monitoring platform

- FastAPI backend with auth, server CRUD, metrics collection
- Web dashboard with dark theme, server cards, SSH terminal (xterm.js)
- Telegram bot with inline keyboards, server management, reboot
- Telegram Mini App for mobile monitoring
- Background monitoring via asyncssh (CPU, RAM, Disk, Network, Uptime)
- Alert system with configurable thresholds
- WebSocket SSH terminal in browser
- One-command install script
- Systemd service configuration

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/services/ssh_manager.py

@@ -0,0 +1,69 @@
+import asyncio
+import logging
+from typing import Dict, Optional
+
+import asyncssh
+
+logger = logging.getLogger(__name__)
+
+active_sessions: Dict[str, asyncssh.SSHClientConnection] = {}
+
+
+async def create_ssh_session(server: dict) -> Optional[asyncssh.SSHClientConnection]:
+    """Create SSH connection to server."""
+    try:
+        conn_kwargs = {
+            "host": server["host"],
+            "port": server.get("port", 22),
+            "username": server.get("username", "root"),
+            "known_hosts": None,
+            "connect_timeout": 15,
+        }
+
+        if server.get("password"):
+            conn_kwargs["password"] = server["password"]
+        elif server.get("ssh_key"):
+            conn_kwargs["client_keys"] = [server["ssh_key"]]
+
+        conn = await asyncssh.connect(**conn_kwargs)
+        active_sessions[server["host"]] = conn
+        return conn
+
+    except Exception as e:
+        logger.error(f"SSH connection failed to {server['host']}: {e}")
+        return None
+
+
+async def execute_command(server: dict, command: str) -> dict:
+    """Execute command on remote server."""
+    try:
+        conn_kwargs = {
+            "host": server["host"],
+            "port": server.get("port", 22),
+            "username": server.get("username", "root"),
+            "known_hosts": None,
+            "connect_timeout": 15,
+        }
+
+        if server.get("password"):
+            conn_kwargs["password"] = server["password"]
+        elif server.get("ssh_key"):
+            conn_kwargs["client_keys"] = [server["ssh_key"]]
+
+        async with asyncssh.connect(**conn_kwargs) as conn:
+            result = await conn.run(command, check=False, timeout=30)
+            return {
+                "stdout": result.stdout,
+                "stderr": result.stderr,
+                "exit_code": result.exit_status,
+            }
+
+    except Exception as e:
+        return {"stdout": "", "stderr": str(e), "exit_code": -1}
+
+
+async def close_session(host: str):
+    """Close SSH session."""
+    conn = active_sessions.pop(host, None)
+    if conn:
+        conn.close()