setup: add "Skip — I'll connect later" option to Claude auth picker

Today the Claude auth picker has only three real-auth options. A user
without a Pro/Max subscription, an OAuth token, or an API key has no
graceful escape — Ctrl-C kills setup entirely.

Add a fourth option that confirms the trade-off (no agent runtime + no
Claude debug help during setup) and, on Yes, marks auth skipped and
lets setup continue. On No, loop back to the picker. Existing
NANOCLAW_SKIP=auth env hatch is unchanged.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

setup/auto.ts

@@ -740,12 +740,38 @@ async function runAuthStep(): Promise<void> {
           label: 'Paste an Anthropic API key',
           hint: 'pay-per-use via console.anthropic.com',
         },
+        {
+          value: 'skip',
+          label: "Skip — I'll connect later",
+          hint: 'not recommended — Claude helps debug setup issues',
+        },
       ],
     }),
-  ) as 'subscription' | 'oauth' | 'api';
+  ) as 'subscription' | 'oauth' | 'api' | 'skip';
   setupLog.userInput('auth_method', method);
   phEmit('auth_method_chosen', { method });
 
+  if (method === 'skip') {
+    const confirmed = ensureAnswer(
+      await p.confirm({
+        message:
+          "Skip Claude sign-in? The agent won't be able to run until you connect, and we won't be able to help debug setup errors.",
+        initialValue: false,
+      }),
+    );
+    if (!confirmed) {
+      // Loop back to the auth picker so they can choose a real method.
+      return runAuthStep();
+    }
+    setupLog.step('auth', 'skipped', 0, { REASON: 'user-skipped' });
+    p.log.warn(
+      brandBody(
+        'Claude sign-in skipped. Re-run setup or run `bash nanoclaw.sh` to finish later.',
+      ),
+    );
+    return;
+  }
+
   if (method === 'subscription') {
     await runSubscriptionAuth();
   } else {