fix(popularity): correct lazy-import path + forward video; single-instance modal

Two bugs in the #26 wiring surfaced live:
- The ⋯ menu lazy-import used "../../viewCountChart.js" which resolves one level
  too high (dist/viewCountChart.js → 404 "Failed to fetch dynamically imported
  module"). Corrected to "../viewCountChart.js" (js/ui → js/viewCountChart.js).
- The video-list context path called handleMoreMenuAction without the video, so
  view-stats hit "No video selected". Forward detail.video.

Also make the popularity modal single-instance: close any open one (proper
subscription/listener cleanup) before opening a new one, so the two menu paths
firing for one click can't stack duplicates or leak a live subscription.

Co-Authored-By: Claude Opus 4.8 <[email protected]>

js/ui/moreMenuController.js

@@ -157,7 +157,7 @@ export default class MoreMenuController {
         ...(detail.dataset || {}),
         eventId: detail.dataset?.eventId || detail.video?.id || "",
       };
-      this.handleMoreMenuAction(detail.action, dataset);
+      this.handleMoreMenuAction(detail.action, dataset, detail.video || null);
     };
 
     if (typeof view.addEventListener === "function") {
@@ -1176,7 +1176,7 @@ export default class MoreMenuController {
           // ignore
         }
         try {
-          const { openPopularityModal } = await import("../../viewCountChart.js");
+          const { openPopularityModal } = await import("../viewCountChart.js");
           openPopularityModal({ video: targetVideo });
         } catch (error) {
           userLogger.warn("[MoreMenu] Failed to open popularity modal:", error);

js/viewCountChart.js

@@ -159,6 +159,9 @@ function el(doc, tag, className, text) {
   return node;
 }
 
+// At most one popularity modal open at a time.
+let activePopularityModal = null;
+
 // Opens the popularity modal for a video. Dependencies are injectable for tests.
 export function openPopularityModal({
   document: doc = typeof document !== "undefined" ? document : null,
@@ -174,6 +177,18 @@ export function openPopularityModal({
   }
   const pointer = pointerInfo.pointer;
 
+  // Close any already-open popularity modal (proper cleanup of its subscription
+  // + listeners) so re-triggering — or two menu paths firing for one click —
+  // can't stack duplicates.
+  if (activePopularityModal) {
+    try {
+      activePopularityModal.close();
+    } catch (error) {
+      // ignore
+    }
+    activePopularityModal = null;
+  }
+
   const root = mount || doc.getElementById("uiOverlay") || doc.body;
   const backdrop = el(doc, "div", "ds-overlay-backdrop popularity-modal__backdrop");
   const dialog = el(doc, "div", "popularity-modal card p-md");
@@ -255,6 +270,9 @@ export function openPopularityModal({
     }
     doc.removeEventListener("keydown", onKeydown, true);
     backdrop.remove();
+    if (activePopularityModal === handle) {
+      activePopularityModal = null;
+    }
   };
 
   function onKeydown(event) {
@@ -298,5 +316,7 @@ export function openPopularityModal({
     devLogger.warn("[popularity] Failed to subscribe to view events:", error);
   }
 
-  return { close };
+  const handle = { close };
+  activePopularityModal = handle;
+  return handle;
 }