fix(reader): hide the chrome when a touch selection starts

pokeChrome's anySelection gate only prevents the chrome from being
raised — if it was already visible when the selection began, it
stayed up. noteSelectionActivity now actively hides it the moment
a selection appears.

web/src/reader/reader.ts

@@ -1082,6 +1082,15 @@ document.addEventListener("alpine:init", () => {
         clearTimeout(this.tapZoneTimer);
         this.tapZoneTimer = null;
       }
+      // Hide the chrome the moment a selection appears — it competes
+      // with the selection popover and handles for screen space.
+      if (hasSelection && this.chromeVisible) {
+        this.chromeVisible = false;
+        if (this.hideTimer) {
+          clearTimeout(this.hideTimer);
+          this.hideTimer = null;
+        }
+      }
     },
     attachTapZoneListeners(surface: HTMLElement, isDoc: boolean) {
       let downX = 0;