Fix PWA install hint dismiss button not hiding the banner.

display: flex on .pwa-hint overrode the hidden attribute; bump static cache to v4.
Co-authored-by: Cursor <cursoragent@cursor.com>

static/style.css

@@ -856,6 +856,10 @@ body.inv-chart-modal-open {
 }
 
 /* PWA install hint */
+.pwa-hint[hidden] {
+  display: none;
+}
+
 .pwa-hint {
   display: flex;
   align-items: flex-start;

static/sw.js

@@ -1,4 +1,4 @@
-const CACHE = "if-viewer-static-v3";
+const CACHE = "if-viewer-static-v4";
 const ASSETS = [
   "/static/style.css",
   "/static/favicon.svg",