fix(core): propagate BeforeModel hook model override end-to-end#24784

SandyTao520 merged 3 commits intogoogle-gemini:maingoogle-gemini/gemini-cli:mainfrom

krishdef7:fix/before-model-hook-model-override-e2ekrishdef7/gemini-cli:fix/before-model-hook-model-override-e2eCopy head branch name to clipboard