fix: apply validateLaunchCmd to manifest fallback path in connect.ts (#2455)

Security: the manifest-derived fallback path in connect.ts bypassed the
validateLaunchCmd() allowlist that guards history-derived commands. A
malicious or modified manifest.json cache could inject arbitrary commands
executed on the remote VM via SSH.

Fixes #2453

Agent: security-auditor

Co-authored-by: B <6723574+louisgv@users.noreply.github.com>
Co-authored-by: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: 3 people

packages/cli/src/commands/connect.ts

@@ -138,6 +138,7 @@ export async function cmdEnterAgent(
       const sep = acc.trimEnd().endsWith("&") ? " " : "; ";
       return acc + sep + part;
     }, "");
+    validateLaunchCmd(remoteCmd);
   }
 
   const agentName = agentDef?.name || agentKey;