[UserList] Add invite button to hover popup (#7144)

* [Client] Send game invites from the user context menu via a private message

The user context menu gains an "Invite to Game" submenu listing the
inviteable games in the room (the inviter's own games, honoring the
buddy-only setting). Picking one opens a private message to the target
user with a cockatrice://joingame link naming the game, so the target
gets a clickable invite instead of a raw URL. Multi-game rooms offer a
picker; a single inviteable game sends directly. Sending a message to
an offline user no longer swallows the draft — it reports that the
user is offline and keeps the typed text.

Took 30 seconds

Took 1 minute

* [Client] Open the invite dialog taller by default without enforcing a minimum size

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Co-authored-by: Lukas Brübach <Bruebach.Lukas@bdosecurity.de>

cockatrice/src/interface/widgets/tabs/tab_supervisor.cpp

@@ -1091,7 +1091,8 @@ QList<GameInviteOption> TabSupervisor::getGameInviteLinksForRoom(int roomId) con
     // The inviter may be in several games of the same room (hosting one and
     // spectating another, for example). Return every game so the caller can
     // let the user choose which one to invite to.
-    for (TabGame *tab : gameTabs) {
+    for (auto it = gameTabs.cbegin(); it != gameTabs.cend(); ++it) {
+        TabGame *tab = it.value();
         GameMetaInfo *metaInfo = tab->getGame()->getGameMetaInfo();
         if (metaInfo->proto().room_id() != roomId) {
             continue;