[DeckShare] Open shared decks via links with a gated preview flow

- Serialized url-chain dispatcher in IntentUrlParser; queue-drained
  urlChainFinished(bool) drives the startup auto-connect fallback
- Open-shared-deck intent with sequential download state machine,
  15s per-item timeout, partial-success offer, livable Cancel via
  ApplicationModal dlg_login_prompt interactive fallback
- Preview dialog: download progress label, share vocab sweep,
  palette-highlight selection frame, Space/Enter keyboard toggle,
  NoFocus checkbox, double-click tile opens immediately
- Confirm-before-server-migration with one-shot restore to the
  previous server on failed/cancelled chains (statusChanged settle
  deferral), hostname-only identity comparisons
- Skip credential link when already connected; arrow-key navigation
  in FlowWidget; card glows use palette highlight
- Address code-review M1-M4 and UI/UX QA blockers 1-2

cockatrice/src/interface/widgets/dialogs/dlg_share_deck.cpp

@@ -72,7 +72,11 @@ void DlgShareDeck::shareFinished(const Response &response, const CommandContaine
 
     const Response_DeckShareCreate &resp = response.GetExtension(Response_DeckShareCreate::ext);
     const QString token = QString::fromStdString(resp.token());
+#if QT_VERSION >= QT_VERSION_CHECK(6, 7, 0)
     const QDateTime expiry = QDateTime::fromSecsSinceEpoch(resp.expires_at(), QTimeZone::UTC);
+#else
+    const QDateTime expiry = QDateTime::fromSecsSinceEpoch(resp.expires_at(), Qt::UTC);
+#endif
 
     const QString link = DeckShareUtils::buildShareLink(client, token);
     DeckShareUtils::copyShareLinkToClipboard(link);

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

@@ -779,7 +779,11 @@ void TabDeckStorage::shareFromTreeFinished(const Response &response, const Comma
     }
     const Response_DeckShareCreate &resp = response.GetExtension(Response_DeckShareCreate::ext);
     const QString token = QString::fromStdString(resp.token());
+#if QT_VERSION >= QT_VERSION_CHECK(6, 7, 0)
     const QDateTime expiry = QDateTime::fromSecsSinceEpoch(resp.expires_at(), QTimeZone::UTC);
+#else
+    const QDateTime expiry = QDateTime::fromSecsSinceEpoch(resp.expires_at(), Qt::UTC);
+#endif
 
     const QString link = DeckShareUtils::buildShareLink(client, token);
     DeckShareUtils::copyShareLinkToClipboard(link);

cockatrice/src/interface/widgets/tabs/visual_deck_storage/tab_deck_storage_visual.cpp

@@ -169,7 +169,11 @@ void TabDeckStorageVisual::shareFinished(const Response &response, const Command
 
     const Response_DeckShareCreate &resp = response.GetExtension(Response_DeckShareCreate::ext);
     const QString token = QString::fromStdString(resp.token());
+#if QT_VERSION >= QT_VERSION_CHECK(6, 7, 0)
     const QDateTime expiry = QDateTime::fromSecsSinceEpoch(resp.expires_at(), QTimeZone::UTC);
+#else
+    const QDateTime expiry = QDateTime::fromSecsSinceEpoch(resp.expires_at(), Qt::UTC);
+#endif
 
     const QString link = DeckShareUtils::buildShareLink(tabSupervisor->getClient(), token);
     DeckShareUtils::copyShareLinkToClipboard(link);