feat(widgets): simplify locations and paid sidebar

Remove deprecated widget locations and widgets, standardize sidebar labels, and render a compact paid-post purchase card in the article sidebar.

assets/css/frontend/widget-batch3c.css

@@ -1,69 +1,7 @@
 /**
- * Batch3c: reviews + highlights.
+ * Batch3c: highlights.
  */
 
-.aksrt-reviews {
-  margin-bottom: 16px;
-  --aksrt-rev-pc: 3;
-  --aksrt-rev-m: 1.2;
-}
-.aksrt-reviews__track {
-  display: grid;
-  grid-auto-flow: column;
-  grid-auto-columns: calc((100% - (var(--aksrt-rev-pc) - 1) * 12px) / var(--aksrt-rev-pc));
-  gap: 12px;
-  overflow-x: auto;
-  scroll-snap-type: x mandatory;
-  padding-bottom: 6px;
-  -webkit-overflow-scrolling: touch;
-}
-@media (max-width: 767.98px) {
-  .aksrt-reviews__track {
-    grid-auto-columns: calc((100% - (var(--aksrt-rev-m) - 1) * 12px) / var(--aksrt-rev-m));
-  }
-}
-.aksrt-reviews__slide { scroll-snap-align: start; min-width: 0; }
-.aksrt-reviews__card {
-  position: relative;
-  border: 1px solid var(--color-line, #e5e7eb);
-  border-radius: 12px;
-  padding: 16px;
-  background: var(--surface-1, #fff);
-  min-height: 100%;
-}
-.aksrt-reviews__head { display: flex; align-items: center; gap: 10px; margin-bottom: 10px; }
-.aksrt-reviews__avatar {
-  width: 44px;
-  height: 44px;
-  border-radius: 50%;
-  object-fit: cover;
-  background: var(--surface-2, #eee);
-  display: inline-flex;
-  align-items: center;
-  justify-content: center;
-  color: #999;
-  flex-shrink: 0;
-}
-.aksrt-reviews__name { font-weight: 700; font-size: 14px; }
-.aksrt-reviews__name a { color: inherit; text-decoration: none; }
-.aksrt-reviews__role { font-size: 12px; color: var(--muted-2-color, #888); }
-.aksrt-reviews__stars { margin-bottom: 8px; font-size: 12px; }
-.aksrt-reviews__stars .is-on { color: #f5a623; }
-.aksrt-reviews__stars .is-off { color: #ddd; }
-.aksrt-reviews__content {
-  font-size: 13px;
-  line-height: 1.55;
-  color: var(--color-ink-2, #444);
-  margin: 0;
-}
-.aksrt-reviews__quote {
-  position: absolute;
-  right: 14px;
-  bottom: 10px;
-  opacity: .12;
-  font-size: 28px;
-}
-
 .aksrt-highlights { margin-bottom: 16px; display: flex; flex-direction: column; gap: 12px; }
 .aksrt-highlights__row {
   display: grid;