feat(antigravity): add Gemini 3.8 Flash medium model

[Lynricsy]

Summary

• add the official Antigravity gemini-3.8-flash-medium slug
• mirror the existing gemini-3.8-flash-high token limits, modalities, and metadata conventions
• expose only low, medium, and high thinking levels; Gemini 3.8 Flash rejects minimal

Rationale

Google Antigravity's Headless documentation lists both gemini-3.8-flash-high and gemini-3.8-flash-medium. CLIProxyAPI refreshes its embedded catalog from this repository at startup, so the Medium route must also exist here to remain available after refresh.

Paired CLIProxyAPI change: router-for-me/CLIProxyAPI#5423

Sources

• Google Antigravity Headless model slugs
• Google Antigravity model availability and reasoning levels
• Gemini 3.8 Flash model capabilities

Verification

• jq -e verified one Medium entry with 1,048,576 context, 65,536 output, and exactly low/medium/high thinking levels

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-09-02T16:22:30.836062Z	1bf1225	PR opened

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[Copilot]

🟢 Approval recommended

The new model entry is consistent with the existing gemini-3.8-flash-high configuration and aligns with the stated thinking-level constraint.

Pull request overview

This PR updates the shared models.json catalog to include the official Google Antigravity model slug gemini-3.8-flash-medium, ensuring downstream consumers (e.g., CLIProxyAPI’s startup refresh) can continue to route to the Medium variant.

Changes:

• Added a new antigravity model entry for gemini-3.8-flash-medium.
• Matched gemini-3.8-flash-high for context length, output token limits, modalities, and metadata structure.
• Restricted thinking levels to low/medium/high (no minimal) for Gemini 3.8 Flash.

File summaries

File	Description
models.json	Adds the gemini-3.8-flash-medium model entry consistent with existing Antigravity Gemini 3.8 Flash conventions.

Review details

• Files reviewed: 1/1 changed files
• Comments generated: 0
• Review effort level: Lite

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