Review findings on #153 (Codex):
- the image serve route allowed only three video types while the gallery
lists seven, so .avi/.mkv/.m4v/.wmv cards opened to a 403; the serve
allow-list now covers every gallery video format
- a settings payload with one invalid field still applied the valid ones
before returning 400; the whole payload is validated first and nothing
changes on failure. webui_display_mode is validated too
Third Windows CI run:
- the same output directory spelled twice (different case or a link) was
listed twice in diagnostics and served roots; both dedupe on the
resolved, case-folded path
- the root-less subfolder test expects the "/" form
Code-quality bot: index definitions are (name, target) pairs instead of
implicitly concatenated strings; redundant local asyncio imports and
two trivial lambdas in test stubs removed.