fix: close WebSocket and auto-remove session on SSH connect failure

When SSH connection fails, close the WebSocket immediately and
auto-remove the pending session after 3 seconds so the user sees
the error message before the panel clears. Prevents stuck sessions.

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

frontend/composables/useTerminal.ts

@@ -84,12 +84,23 @@ export function useTerminal() {
           break
         case 'error':
           term.write(`\r\n\x1b[31mError: ${msg.message}\x1b[0m\r\n`)
+          term.write('\x1b[33mPress any key to close this session.\x1b[0m\r\n')
+          // Mark this connection as failed so onData closes it
+          ws?.close()
           break
       }
     }
 
     ws.onclose = () => {
       term.write('\r\n\x1b[33mConnection closed.\x1b[0m\r\n')
+      // Clean up pending session if connection never succeeded
+      if (pendingSessionId.startsWith('pending-')) {
+        const session = sessions.sessions.find(s => s.id === pendingSessionId)
+        if (session) {
+          // Session was never replaced with a real one — remove after short delay so user sees the error
+          setTimeout(() => sessions.removeSession(pendingSessionId), 3000)
+        }
+      }
     }
 
     // Terminal input → WebSocket