Sync local clipboard to a tab when it becomes visible

Only the visible tab syncs the clipboard, but a tab in the background
missed local clipboard changes and kept a stale remote clipboard when
switched to, so with two RDP/VNC sessions only the one last copied in
worked. A tab now pushes the current local clipboard to its remote on
show.

Bump version to v2026.9.26.2.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/session_tab.h

@@ -24,6 +24,7 @@ class QComboBox;
 class QLabel;
 class QPushButton;
 class QScrollArea;
+class QShowEvent;
 class KodoTerm;
 
 struct SessionUiPreferences
@@ -99,6 +100,11 @@ signals:
     void requestSetClipboardText(const QString& text);
     void requestProvideUsername(const QString& username);
 
+protected:
+    // A tab that wasn't in front while the local clipboard changed missed
+    // that change (only the visible tab syncs), so catch it up on show.
+    void showEvent(QShowEvent* event) override;
+
 private slots:
     void onBackendStateChanged(SessionState state, const QString& message);
     void onBackendEventLogged(const QString& message);
@@ -166,6 +172,7 @@ private:
                             std::function<void(std::optional<QString>)> callback,
                             bool maskInput = true);
     void hidePasswordPrompt();
+    void pushLocalClipboardToRemote();
     bool validateProfileForConnect();
     void appendEvent(const QString& message);
     void setState(SessionState state, const QString& message);