Put the blob command on PATH and reapply the default theme when it is missing

session/profile.sh

@@ -0,0 +1,6 @@
+# Put the blob command on PATH for login shells. The graphical session gets the
+# same environment from ~/.config/uwsm/env.d/10-blob.
+
+if [ -r "$HOME/.local/share/blob/session/env-bootstrap" ]; then
+  . "$HOME/.local/share/blob/session/env-bootstrap"
+fi