sloproxy

fix(auth): isolate subagent session affinity for antigravity and gemini master

- Prevent subagent sessions from inheriting parent credentials on Antigravity and Gemini providers and models to mitigate concurrency rate limiting. - Avoid aliasing subagent session keys to parent fallback keys or mutating parent bindings during subagent result handling. Closes: #5364


+537 -5
2 changed files