fix: make HUD overlay and source selector follow across macOS Spaces

Both windows had alwaysOnTop but lacked setVisibleOnAllWorkspaces, so
they stayed pinned to the Space they were first opened on. Users moving
to a different virtual desktop would lose sight of the overlay.

Calls setVisibleOnAllWorkspaces(true, { visibleOnFullScreen: true })
on macOS only — no-op on Windows/Linux so cross-platform behaviour is
unchanged.

electron/windows.ts

@@ -51,6 +51,12 @@ export function createHudOverlayWindow(): BrowserWindow {
 		},
 	});
 
+	// Follow the user across macOS Spaces (virtual desktops).
+	// Without this the HUD stays pinned to the Space it was first opened on.
+	if (process.platform === "darwin") {
+		win.setVisibleOnAllWorkspaces(true, { visibleOnFullScreen: true });
+	}
+
 	win.webContents.on("did-finish-load", () => {
 		win?.webContents.send("main-process-message", new Date().toLocaleString());
 	});
@@ -142,6 +148,12 @@ export function createSourceSelectorWindow(): BrowserWindow {
 		},
 	});
 
+	// Follow the user across macOS Spaces so the selector appears on the
+	// active desktop regardless of where the HUD was originally opened.
+	if (process.platform === "darwin") {
+		win.setVisibleOnAllWorkspaces(true, { visibleOnFullScreen: true });
+	}
+
 	if (VITE_DEV_SERVER_URL) {
 		win.loadURL(VITE_DEV_SERVER_URL + "?windowType=source-selector");
 	} else {