[Code Quality] Add antigravity engine to docs/reference/engines.md to fix runtime/docs catalog drift

[github-actions]

Description

The Schema Consistency Check (2026-07-27) found that the antigravity engine is supported at runtime but completely absent from the documentation.

Specifically:

• pkg/workflow/engine_definition.go lists antigravity as a built-in engine
• Real compiled workflows reference .antigravity agent folders and firewall model groups confirming live runtime support
• docs/src/content/docs/reference/engines.md omits antigravity entirely

Suggested Changes

1. Add antigravity to docs/src/content/docs/reference/engines.md wherever built-in engine choices are enumerated
2. Optionally: add a regression test or doc-generation check that diffs the runtime engine catalog against engines.md to prevent future drift

Files Affected

• docs/src/content/docs/reference/engines.md — add antigravity entry
• pkg/workflow/engine_definition.go — reference source of truth

Success Criteria

• engines.md lists antigravity alongside claude, codex, copilot, gemini, opencode, pi
• Users relying on antigravity can find documentation for it
• Optionally: a CI check prevents engine catalog from drifting again

Source

Extracted from Schema Consistency Check #48302

Priority

High — Users can currently use a supported engine with no documentation

🔍 Task mining by Discussion Task Miner - Code Quality Improvement Agent · sonnet46 · 53.1 AIC · ⌖ 8.15 AIC · ⊞ 7.2K · ◷

• expires on Jul 28, 2026, 12:03 AM UTC-08:00

[github-actions]

This issue was automatically closed because it expired on 2026-07-28T08:03:29.154Z.

Closed by Workflow