Make setup ISO-only

Remove legacy online installer entrypoints, collapse migrations for 4.0, and move setup responsibilities into target-side system, hardware, and user commands.

test/shell.d/runtime-smoke-test.sh

@@ -13,6 +13,7 @@ cleanup() {
     wait "$QS_PID" 2>/dev/null || true
   fi
   [[ -n $TMPDIR && -d $TMPDIR ]] && rm -rf "$TMPDIR"
+  return 0
 }
 trap cleanup EXIT