Propagate writeShellApplication runtimeInputs via propagatedNativeBuildInputs
The switch from nix-print-dev-env to devShellTools (a354771) broke runtimeInputs visibility in -env container scripts. writeShellApplication embeds runtimeInputs in the wrapper's own PATH, but $stdenv/setup (which the -env scripts source) only walks buildInputs/nativeBuildInputs — not the internal PATH of wrappers within those inputs. The previous fix (76d6b37) added curl explicitly to buildInputs, but this is fragile: any future runtimeInputs change requires a parallel edit in the shell's input lists. Instead, use propagatedNativeBuildInputs on the wrapper derivation. When $stdenv/setup processes wrapped-cabal from nativeBuildInputs, it transitively follows propagatedNativeBuildInputs and adds curl (and cabal-install) to PATH for the whole environment. This is the standard Nix mechanism for transitive dependency propagation. Applies to all four shell definitions: dynamic, static, cross-js, cross-windows. Removes the explicit curl additions from 76d6b37.