Stop hiding the top bar globally -- it hid the Save button on entity edit forms

.top-bar was unconditionally hidden on every page (admin_chrome library)
on the assumption it always renders empty, which held on our own pages
but not on entity edit forms, where Gin puts the page's local actions --
Save included -- inside .top-bar. Folded it into the same route-scoped
library as the admin sidebar (renamed hide_admin_sidebar ->
hide_admin_chrome) so both are hidden only on our front-end routes and
real admin pages keep a working Save button.

web/modules/custom/figli_compta_ledger/css/admin-chrome.css

@@ -1,23 +1,7 @@
-/* Core Navigation's top bar (`.top-bar`) only shows itself when its
-   tools/context/actions regions are non-empty -- but with no blocks placed
-   there, the regions still contain whitespace text nodes from the Twig
-   loop scaffolding, which defeats the `:not(:empty)` check. Result: an
-   empty top bar renders anyway, with the page content pushed down to make
-   room for it. We only use the Gin sidebar (the left icon rail), so force
-   the phantom bar off and collapse the space it would otherwise reserve. */
-.top-bar {
-  display: none !important;
-}
-
-.top-bar ~ .dialog-off-canvas-main-canvas {
-  margin-block-start: 0 !important;
-}
-
 /* Grand livre / Dashboard switcher, top-right of both pages. Only present
-   on those two custom routes, but attached here (already loaded on every
-   page for the phantom-top-bar fix above) rather than duplicated between
-   home.css and dashboard.css -- and defined with its own explicit colors
-   rather than relying on either page's #figli-*-app-scoped custom
+   on those two custom routes, but attached here rather than duplicated
+   between home.css and dashboard.css -- and defined with its own explicit
+   colors rather than relying on either page's #figli-*-app-scoped custom
    properties, since this <nav> sits outside both of those elements. */
 .figli-page-nav {
   display: flex;