CLI, App, and IDE: Clean up the model picker

The model picker on all interfaces has become too bloated and confusing. It should be pruned to reduce overlap.

• On Twitter, both @tibo-openai and @ambrosino-oai have said that gpt-5.4 is the model. It should be the default.
• gpt-5.3-codex and gpt-5.2 should have "latest" removed from their descriptions.
• Superseded models should be removed from the picker entirely. This includes gpt-5.2-codex, gpt-5.1-codex-max, and gpt-5.2. There's a case for gpt-5.1-codex-mini sticking around because non-pro users don't have access to gpt-5.3-codex-spark.

Here's what the model picker should look like:
<img width="826" height="166" alt="Image" src="https://github.com/user-attachments/assets/8104047d-a9f1-4fd3-9680-1555e2455b2c" />

The downsides are minimal because the picker provides clear guidance on how to use legacy models.