[DeckShare] Open shared decks via links with a gated preview flow (#7244)

* [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

* [DeckShare] End the open-shared-deck files with a trailing newline

* [DeckShare] Forward a dependency's cancellation as the owner's own

* [DeckShare] Let intent chains opt into the link sign-in dialog

* [DeckShare] Track link-intent chains per-run so each can restore its own session

* [Settings] Match a server on the exact host and port when adding it

* [DeckShare] Confirm the share link's target server before opening a deck

* [DeckShare] Reformat the link sign-in intent constructor

* [DeckShare] Time the share-list round trip and backstop silently-destroyed intent chains

* [Client] Drain a single-instance payload before its handlers read the socket again

* [Client] Treat a busy single-instance primary as alive instead of stealing its socket

* [DeckShare] Keep arrow-key navigation between flow items inside a scroll area

* [Client] Skip the startup connection when a macOS URL launch owns the connection

* [Client] Redact share secrets from activation URL logs

* [Client] Make the link-connection gates port-aware and keyboard-safe

Second-pass review notes for the shared-deck link flow (Cockatrice#7244):

- FlowWidget arrow-key navigation is opt-in via addNavigableWidget, so
  combo/spin controls on the analytics flows keep their own arrow keys
- isConnectedTo and the open-deck/join-game preconditions compare the
  configured server port alongside the host, so a same-host/different-port
  link cannot resolve its share token or game id on the wrong instance
- the link sign-in dialog reuses an existing server entry's saved name
  instead of renaming it to the raw hostname
- skipStartupAutoConnect is cleared once the launch chain connects, so a
  later mid-session declined link cannot fire the startup fallback
- the plain-launch path of SingleInstanceManager no longer blocks on the
  primary's ACK
- link- and server-supplied text is html-escaped in the confirm prompts and
  shared-deck preview so markup cannot spoof the shown messages

---------

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

libcockatrice_settings/libcockatrice/settings/servers_settings.cpp

@@ -171,7 +171,12 @@ void ServersSettings::addNewServer(const QString &saveName,
                                    bool savePassword,
                                    const QString &site)
 {
-    if (updateExistingServer(saveName, serv, port, username, password, savePassword, site)) {
+    // Match the exact host-plus-port server the caller is adding, so a link or
+    // public-server list entry cannot clobber the port (and credentials) of an
+    // unrelated entry that happens to share the same hostname.
+    const int existingIndex = findServerIndex(serv, port);
+    if (existingIndex >= 0) {
+        updateServerFields(existingIndex, saveName, username, password, savePassword, site);
         return;
     }
 
@@ -271,22 +276,7 @@ bool ServersSettings::updateExistingServer(QString saveName,
     for (int i = 0; i <= size; ++i) {
         if (serv == getValue(QString("server%1").arg(i), "server", "server_details").toString()) {
             setValue(port, QString("port%1").arg(i), "server", "server_details");
-            if (!username.isEmpty()) {
-                setValue(username, QString("username%1").arg(i), "server", "server_details");
-            }
-
-            if (savePassword && !password.isEmpty()) {
-                setValue(password, QString("password%1").arg(i), "server", "server_details");
-            } else {
-                setValue(QString(), QString("password%1").arg(i), "server", "server_details");
-            }
-
-            if (!site.isEmpty()) {
-                setValue(site, QString("site%1").arg(i), "server", "server_details");
-            }
-
-            setValue(savePassword, QString("savePassword%1").arg(i), "server", "server_details");
-            setValue(saveName, QString("saveName%1").arg(i), "server", "server_details");
+            updateServerFields(i, saveName, username, password, savePassword, site);
 
             return true;
         }
@@ -294,6 +284,31 @@ bool ServersSettings::updateExistingServer(QString saveName,
     return false;
 }
 
+void ServersSettings::updateServerFields(int index,
+                                         const QString &saveName,
+                                         const QString &username,
+                                         const QString &password,
+                                         bool savePassword,
+                                         const QString &site)
+{
+    if (!username.isEmpty()) {
+        setValue(username, QString("username%1").arg(index), "server", "server_details");
+    }
+
+    if (savePassword && !password.isEmpty()) {
+        setValue(password, QString("password%1").arg(index), "server", "server_details");
+    } else {
+        setValue(QString(), QString("password%1").arg(index), "server", "server_details");
+    }
+
+    if (!site.isEmpty()) {
+        setValue(site, QString("site%1").arg(index), "server", "server_details");
+    }
+
+    setValue(savePassword, QString("savePassword%1").arg(index), "server", "server_details");
+    setValue(saveName, QString("saveName%1").arg(index), "server", "server_details");
+}
+
 int ServersSettings::findServerIndex(const QString &host, const QString &port) const
 {
     int size = getValue("totalServers", "server", "server_details").toInt();
@@ -310,6 +325,21 @@ int ServersSettings::findServerIndex(const QString &host, const QString &port) c
     return -1;
 }
 
+int ServersSettings::findHostIndex(const QString &host) const
+{
+    int size = getValue("totalServers", "server", "server_details").toInt();
+
+    for (int i = 0; i <= size; ++i) {
+        QString storedHost = getValue(QString("server%1").arg(i), "server", "server_details").toString();
+
+        if (storedHost.compare(host, Qt::CaseInsensitive) == 0) {
+            return i;
+        }
+    }
+
+    return -1;
+}
+
 bool ServersSettings::hasUsername(const QString &host, const QString &port) const
 {
     int index = findServerIndex(host, port);