TerminalApp: foreground target window in FocusProtocolPane

src/cascadia/TerminalApp/TerminalPage.Protocol.cpp

@@ -728,6 +728,21 @@ namespace winrt::TerminalApp::implementation
             if (!paneId)
                 co_return false;
 
+            // Bring this window to the foreground. `focus_pane` can target a
+            // pane that lives in a *different* window than the one driving the
+            // request (e.g. Enter on a session in window B whose pane lives in
+            // window A). The `_SetFocusedTab` / `FocusPane` calls below only
+            // move XAML focus *within* this window — they don't activate the OS
+            // window, and when the target pane is already the focused pane here
+            // they no-op entirely. Without an explicit summon the window would
+            // then stay in the background whenever it happened to already have
+            // the target pane focused, while working only when focus actually
+            // transitioned (an accidental side effect). Raising
+            // `SummonWindowRequested` mirrors the desktop-notification
+            // activation path (TabManagement.cpp) and makes `focus_pane`
+            // reliably surface the window regardless of its prior focus state.
+            SummonWindowRequested.raise(nullptr, nullptr);
+
             _SetFocusedTab(tab);
 
             // The pane may be a currently-stashed agent pane (Ctrl+Shift+. /