[eric] browser: Ctrl/Cmd+R reloads the last-interacted browser, else the app

frontend/src/shared/browserFocus.ts

@@ -0,0 +1,17 @@
+// Tracks which browser card the user last interacted with (clicked into its page or its chrome),
+// so global shortcuts (Ctrl+R reload, Ctrl +/- zoom, Ctrl+Tab) target THAT browser instead of a
+// guess. Module-level and imperative on purpose: shortcut handlers read it on keydown, so no React
+// re-render is needed. Cleared the moment the user clicks anything that isn't a browser card.
+let lastInteractedBrowserId: string | null = null;
+
+export function setLastInteractedBrowser(browserId: string): void {
+  lastInteractedBrowserId = browserId;
+}
+
+export function clearLastInteractedBrowser(): void {
+  lastInteractedBrowserId = null;
+}
+
+export function getLastInteractedBrowser(): string | null {
+  return lastInteractedBrowserId;
+}