Fix compressed gallery photo-detail metadata panel (#314)

The photo-detail view is an absolutely-positioned (inset:0) overlay
inside .gallery-images-container, so its height resolved to the photo
grid sitting behind it. When the library has only a few photos that grid
is short, which crushed the detail view: the image was clipped and the
metadata sidebar (overflow-y:auto) was squeezed into a tiny,
internally-scrolling strip. With a large library the grid is tall, which
is why the panel looked fine in the demo video but cramped for users with
few photos.

When the detail view is open, hide the grid-view siblings and drop the
overlay into normal flow so the container -- and the window, up to its
existing 92vh max-height -- sizes to the detail's own content (image +
metadata). Nothing is clipped or squeezed regardless of how many photos
exist. Works on both desktop and the mobile full-screen sheet; the grid,
albums and editor views keep sizing to their own content.

Also add before/after comparison screenshots (docs/gallery-314-*.png).

static/style.css

@@ -16092,6 +16092,30 @@ body:not(.email-doc-split-active) #email-lib-modal.email-lib-fullscreen:not(.mod
 .gallery-modal-content:has(#gallery-editor-container[style*="flex"]) {
   height: 92vh;
 }
+/* Photo-detail view sizing (issue #314).
+   The detail view is rendered as a `position:absolute; inset:0` overlay
+   *inside* `.gallery-images-container`, painted over the photo grid. Because
+   it's absolutely positioned it can't contribute to the container's height —
+   the container (and therefore the overlay's `inset:0` box) collapses to the
+   height of the grid sitting behind it. When the library only has a few
+   photos that grid is short, so the detail view is crushed: the image is
+   clipped and the metadata sidebar (`overflow-y:auto`) is squeezed into a
+   tiny, internally-scrolling strip. (With a large library the grid is tall,
+   which is why it looked fine in the demo video but cramped for users with
+   few photos.)
+   Fix: when the detail view is open, hide the grid-view siblings and drop the
+   overlay into normal flow. The container — and the window, up to its 92vh
+   max-height — then sizes to the detail's own content (image + metadata), so
+   nothing is clipped or squeezed regardless of how many photos exist. Scoped
+   via the detail element's inline `display:flex` so the grid / albums views
+   keep sizing to their own content. Works on both desktop and the mobile
+   full-screen sheet. */
+#gallery-images-container:has(> #gallery-detail[style*="flex"]) > *:not(#gallery-detail) {
+  display: none !important;
+}
+#gallery-images-container:has(> #gallery-detail[style*="flex"]) > #gallery-detail {
+  position: static;
+}
 /* Containing block for the photo-detail overlay — keeps it inside the body
    so it sits below the modal header and the tab strip instead of covering them. */
 .gallery-images-container { position: relative; }