fix: Use _path_prepend in profile.d/krew and profile.d/anyenv

Both prepended to PATH directly, so re-sourcing them in the same
shell would duplicate entries — same issue _path_append already
fixed for profile.d/path and rc.d/rvm. _path_prepend keeps the same
priority ordering (these paths still take precedence over the rest
of PATH) while adding the dedup guard.

profile.d/krew

@@ -1,3 +1,3 @@
 if (command -v krew &>/dev/null); then
-	export PATH="${KREW_ROOT:-${HOME}/.krew}/bin:${PATH}"
+	_path_prepend "${KREW_ROOT:-${HOME}/.krew}/bin"
 fi