node-tools loaded every bundle once at start, so a bundle delivered after
it started (mesh-files on shanks, 2026-10-25 12:08) went unserved until a
hand restart, and a missing file was said as "not executable". The
runtime now watches the entrypoints' directories with inotify, loads a
module again once a burst of changes settles, and discovery answers with
what is served now. A bundle that cannot start says it does not exist, is
not executable with its mode, or the exec error.
Tests: 1945/AC19-AC22 in internal/runtime/reload_test.go.