fix(auth): Improve OAuth credential detection and startup warning

- Enhanced getClaudeAuthIndicators() to return detailed check information
  including file paths checked and specific error details for debugging
- Added debug logging to server startup credential detection for easier
  troubleshooting in Docker environments
- Show paths that were checked in the warning message to help users debug
  mount issues
- Added support for CLAUDE_CODE_OAUTH_TOKEN environment variable
- Return authType in verify-claude-auth response to distinguish between
  OAuth and CLI authentication methods
- Updated UI to show specific success messages for Claude Code subscription
  vs generic CLI auth
- Added Docker troubleshooting tips to sandbox risk dialog
- Added comprehensive unit tests for OAuth credential detection scenarios

Closes #721

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

apps/ui/src/components/dialogs/sandbox-risk-dialog.tsx

@@ -69,6 +69,29 @@ export function SandboxRiskDialog({ open, onConfirm, onDeny }: SandboxRiskDialog
                 For safer operation, consider running Automaker in Docker. See the README for
                 instructions.
               </p>
+
+              <div className="bg-muted/50 border border-border rounded-lg p-4 space-y-2">
+                <p className="text-sm font-medium text-foreground">
+                  Already running in Docker? Try these troubleshooting steps:
+                </p>
+                <ul className="text-sm text-muted-foreground list-disc list-inside space-y-1">
+                  <li>
+                    Ensure <code className="bg-muted px-1 rounded">IS_CONTAINERIZED=true</code> is
+                    set in your docker-compose environment
+                  </li>
+                  <li>
+                    Verify the server container has the environment variable:{' '}
+                    <code className="bg-muted px-1 rounded">
+                      docker exec automaker-server printenv IS_CONTAINERIZED
+                    </code>
+                  </li>
+                  <li>Rebuild and restart containers if you recently changed the configuration</li>
+                  <li>
+                    Check the server logs for startup messages:{' '}
+                    <code className="bg-muted px-1 rounded">docker-compose logs server</code>
+                  </li>
+                </ul>
+              </div>
             </div>
           </DialogDescription>
         </DialogHeader>