feed: add public popularity (views-over-time) chart in the ⋯ menu (#26)

A "Popularity" item in the video ⋯ menu opens a public views-over-time chart
(view data is public). Builds on the now-trustworthy view counts (#4).

- buildViewCountTimeSeries buckets raw kind-30079 view events by the counter's
  dedupe window (one view per viewer per day) into a cumulative series.
- buildViewCountChartSvg renders a token-colored (currentColor / text-accent)
  SVG area+line chart — no charting library, no raw colors.
- The modal fetches via listVideoViewEventsWithDefaultClient, shows the total,
  and updates LIVE by subscribing to view events (debounced re-render); cleans
  up on close (Esc / backdrop / ✕). Lazy-loaded from the menu handler so it
  only ships when opened.

New size tokens for the modal; reuses .ds-overlay-backdrop for the scrim.

Tests: tests/view-count-chart.test.mjs (cumulative dedupe, junk filtering,
SVG line/area + empty/single-point).

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

js/ui/moreMenuController.js

@@ -1162,6 +1162,28 @@ export default class MoreMenuController {
           .catch(() => this.callbacks.showError("Failed to copy the link."));
         break;
       }
+      case "view-stats": {
+        const targetVideo =
+          video || (context === "modal" ? currentVideo : null) || currentVideo;
+        if (!targetVideo) {
+          this.callbacks.showError("No video selected.");
+          break;
+        }
+        // Dismiss the menu, then open the public popularity chart (lazy-loaded).
+        try {
+          this.activePopover?.close?.();
+        } catch (error) {
+          // ignore
+        }
+        try {
+          const { openPopularityModal } = await import("../../viewCountChart.js");
+          openPopularityModal({ video: targetVideo });
+        } catch (error) {
+          userLogger.warn("[MoreMenu] Failed to open popularity modal:", error);
+          this.callbacks.showError("Couldn’t open popularity.");
+        }
+        break;
+      }
       case "remove-history": {
         await this.callbacks.handleRemoveHistoryAction(dataset);
         break;