sloproxy

perf(executor): replace `sjson.SetBytes` with optimized helpers for conditional payload updates master

- Introduced `SetStringIfDifferent`, `SetBoolIfDifferent`, and similar helpers in `payload_helpers` to avoid unnecessary writes during JSON modifications. - Simplified message patching in `kimi_executor` for reasoning and tool call adjustments. - Updated all executors (Gemini, Codex, XAI, Antigravity, etc.) to use the new helpers, enhancing readability and potentially reducing overhead. - Removed obsolete `filterKimiEmptyAssistantMessages` function in `kimi_executor`.