Run 48's Linux leg flaked: full_res_worker_outlives_a_dropped_project panicked with "the render manager failed to start" while all 236 other tests passed -- a worker-pool startup race under full-suite parallelism, not a regression (the same binary passes locally and passed on the previous commit). Mirror the Windows job's retry-once policy and make ensure_render_manager log the underlying init error so the next flake is diagnosable. The Windows leg's real failure (gpui_widgets referenced SurfaceSource::Texture, which only exists on linux/freebsd) is fixed in the gpui submodule bump of the previous commit.