fix: add CSRF protection in plus-checkout.js

[anupamme]

Summary

Fix high severity security issue in flows/openai/content/plus-checkout.js.

Vulnerability

Field	Value
ID	V-002
Severity	HIGH
Scanner	multi_agent_ai
Rule	V-002
File	flows/openai/content/plus-checkout.js:801
Assessment	Likely exploitable
CWE	CWE-352

Description: Payment initiation occurs entirely client-side using a Bearer token obtained from the session endpoint. No CSRF protection, re-authentication, or visible server-side authorization checks are present in the client code. While the actual authorization enforcement should be on ChatGPT's backend, this client-side implementation assumes the backend is secure and provides no additional safeguards.

Evidence

Exploitation scenario: If an attacker achieves JavaScript execution in the chatgpt.com context (via XSS on that domain), they can call this function directly.

Scanner confirmation: multi_agent_ai rule V-002 flagged this pattern.

Production code: This file is in the production codebase, not test-only code.

Threat Model Context

This is a Node.js library - vulnerabilities affect downstream consumers who use this package.

Changes

• flows/openai/content/plus-checkout.js

Behavior Preservation

The change is scoped to 1 file on the vulnerable path, and the project's existing tests still pass, so intended behavior is unchanged.

Verification

• Build passes
• Scanner re-scan confirms fix
• LLM code review passed

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Automated security fix by OrbisAI Security