fix(explore): stop hiding the request badge until the row is hovered

The badge on a row you do not own was transparent until the row was
hovered or focused. That rule was inherited from the green ticks it
replaced, and it does not survive the reason those went: a tick marked
the *common* case, while this marks the rows that are not here. A mark
on the exception is the information on this page, and one that appears
only under the pointer cannot be seen, counted, or reached by anyone
driving the app with a finger.

The repaint half of #33 is fixed in #82; this is only the visibility,
rebased to leave that alone.

Refs #33

frontend/src/components/explore-album-details/explore-album-details.ts

@@ -662,34 +662,21 @@ export class ExploreAlbumDetails extends LitElement implements ContextMenuHost {
                 font-weight: 400;
             }
 
-            /* The request control is only offered where there is
-             * something to request, and only when the row is being
-             * attended to — a column of plus signs down a mostly-owned
-             * album is the clutter the green ticks were.
+            /* The request control is offered on every row that has
+             * something to request, and is not revealed on hover.
              *
-             * Hidden with opacity, never display:none or visibility,
-             * so it keeps its place in the layout (rows do not reflow
-             * as the pointer moves) and stays in the tab order and the
-             * accessibility tree.  focus-within is what makes it
-             * reachable without a mouse: tabbing to the button reveals
-             * it, and the row's own focus reveals it before you get
-             * there. */
+             * It used to be transparent until the row was hovered or
+             * focused, on the reasoning that a column of plus signs
+             * down a mostly-owned album is clutter. That reasoning was
+             * inherited from the green ticks it replaced and does not
+             * survive the rule those were removed for: a tick marked
+             * the *common* case, while this marks the rows that are
+             * **not** here. A mark on the exception is the information
+             * on this page — and one that appears only under the
+             * pointer cannot be seen, counted, or reached by anyone
+             * driving this with a finger. */
             .track-row .track-request {
                 flex-shrink: 0;
-                opacity: 0;
-                transition: opacity 0.12s ease;
-            }
-
-            .track-row:hover .track-request,
-            .track-row:focus-within .track-request,
-            .track-row .track-request:focus-visible {
-                opacity: 1;
-            }
-
-            @media (prefers-reduced-motion: reduce) {
-                .track-row .track-request {
-                    transition: none;
-                }
             }
         `,
     ];