Merge upstream master and move the reveal docs into docs/

Upstream moved the documentation sources from doc/ to docs/ (#7584), so the
page this branch adds now belongs under docs/doxygen/pages/user_documentation/
gameplay/. The index.md edit auto-merged onto the moved file, but the new page
stayed at the old path, and GitHub's merge engine reported a conflict in
index.md because the file it edits was deleted upstream.

No source changes: the merge is upstream/master as-is plus the doc relocation.

libcockatrice_game/libcockatrice/game/zones/view_zone_logic.cpp

@@ -7,6 +7,7 @@
 #include <QtGlobal>
 #include <libcockatrice/interfaces/interface_interface_settings_provider.h>
 #include <libcockatrice/settings/interface_settings.h>
+#include <libcockatrice/utility/zone_names.h>
 
 class PlayerLogic;
 class QObject;
@@ -36,6 +37,11 @@ bool ZoneViewZoneLogic::getCloseEmptyCardView() const
     return interfaceSettings ? interfaceSettings->getCloseEmptyCardView() : true;
 }
 
+bool ZoneViewZoneLogic::isLibraryEdgeView() const
+{
+    return origZone != nullptr && numberCards > 0 && origZone->getName() == ZoneNames::DECK;
+}
+
 /**
  * Checks if inserting a card at the given position requires an actual new card to be created and added to the view.
  * Also does any cardId updates that would be required if a card is inserted in that position.

libcockatrice_game/libcockatrice/game/zones/view_zone_logic.h

@@ -82,6 +82,27 @@ public:
         return isReversed;
     }
 
+    /**
+     * @brief Whether this view is a limited look at one end of a library.
+     *
+     * Only scry/surveil-style views of the top or bottom cards of a deck
+     * qualify. Full-zone views, revealed-card views and views of other zones
+     * do not, because their first and last cards have no library edge meaning.
+     */
+    [[nodiscard]] bool isLibraryEdgeView() const;
+
+    /** @brief Whether the first card in the view is the top card of the library. */
+    [[nodiscard]] bool showsTopOfLibrary() const
+    {
+        return isLibraryEdgeView() && !isReversed;
+    }
+
+    /** @brief Whether the last card in the view is the bottom card of the library. */
+    [[nodiscard]] bool showsBottomOfLibrary() const
+    {
+        return isLibraryEdgeView() && isReversed;
+    }
+
     CardZoneLogic *getOriginalZone() const
     {
         return origZone;