fix(pyenv): load managed Python in every zsh

The pyenv fragment lived in the interactive overlay, so agents and zsh -c fell back to system Python. Install it through the always-on fragment path and keep XDG destinations aligned with the loader.

zsh/pyenv.zsh

@@ -0,0 +1,7 @@
+# pyenv (Python Version Manager), always-on via ~/.zshenv
+export PYENV_ROOT="${PYENV_ROOT:-$HOME/.pyenv}"
+[[ -d "$PYENV_ROOT/bin" ]] && export PATH="$PYENV_ROOT/bin:$PATH"
+[[ -d "$PYENV_ROOT/shims" ]] && export PATH="$PYENV_ROOT/shims:$PATH"
+if [[ -o interactive ]] && command -v pyenv &> /dev/null; then
+  eval "$(pyenv init - zsh)"
+fi