Clarify that OpenAI Realtime voice is billed through OpenAI Platform credits, not Codex/ChatGPT subscription quota, for Voice Call and Control UI Talk.
Document the direct Platform API key path, the `openai-codex` OAuth client-secret path, the quota symptom, and the Platform billing fix. Keep the changelog note crediting @lonexreb.
Closes#76498.
Co-authored-by: lonexreb <reach2shubhankar@gmail.com>