[Feature]: Add new GPT‑4.x series, new o‑series, and computer‑use‑preview to Image Token Calculator

[jamesmcroft]

Feature Description

Extend to include the following available model variants:

• gpt-4.1
• gpt-4.1-mini
• gpt-4.1-nano
• o3
• o4-mini
• o1
• o1-pro
• computer-use-preview
• gpt-4.5-preview

Motivation

OpenAI has shipped new multimodal models since the calculator’s last update. Without those entries, developers can’t quickly compare token costs and risk over‑ or under‑estimating budget needs. Adding these options will keep the tool aligned with the current service catalog, improve adoption, and reduce support questions around pricing.