feat: UI animation enhancements across all major pages

P1 - Critical UX feedback:
- Add scale-in + slide-up-in entrance animations to profile popover and notification panel
- Port SmoothedProgressBar to EcommercePage (4 generation tools: clone, detail, tryOn, productSet)
- Add result-reveal stagger animation to ecommerce result grids
- Add heart-pop spring animation to CommunityPage favorite toggle

P2 - Visual polish:
- Add scroll-entrance IntersectionObserver animations for HomePage feature sections and experience section
- Add chat-message-in entrance animation to WorkbenchPage message rows
- Fix prefers-reduced-motion accessibility in WelcomeSplash canvas (skip animation, instant entry)

P3 - CSS consolidation:
- Remove conflicting .page-motion definition from legacy-pages.css (keep translateY version from legacy-components.css)
- Consolidate skeleton-shimmer: remove opacity-pulse keyframe from primitives.css, unify with gradient sweep
- Wire up --ease-spring token for heart-pop animation
- Add :active press states (scale 0.97) to topbar buttons, brand lockup

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/styles/pages/ecommerce.css

@@ -9,6 +9,48 @@
   font-family: Inter, "PingFang SC", "Microsoft YaHei", Arial, sans-serif;
 }
 
+/* Ecommerce generation progress bar */
+.ecommerce-progress-bar {
+  display: flex;
+  align-items: center;
+  gap: 12px;
+  padding: 10px 16px;
+  border-radius: var(--radius-sm, 10px);
+  background: rgba(var(--accent-rgb, 0, 255, 136), 0.08);
+  border: 1px solid rgba(var(--accent-rgb, 0, 255, 136), 0.18);
+  margin: 8px 0;
+}
+
+.ecommerce-progress-bar__label {
+  font-size: 13px;
+  font-weight: 700;
+  color: var(--fg-muted, #aeb8b1);
+  white-space: nowrap;
+}
+
+.ecommerce-progress-bar__track {
+  flex: 1;
+  height: 6px;
+  border-radius: 999px;
+  background: rgba(var(--accent-rgb, 0, 255, 136), 0.12);
+  overflow: hidden;
+}
+
+.ecommerce-progress-bar__fill {
+  height: 100%;
+  border-radius: 999px;
+  background: var(--accent, #00ff88);
+  transition: width 80ms linear;
+}
+
+.ecommerce-progress-bar__value {
+  font-size: 12px;
+  font-weight: 900;
+  color: var(--accent, #00ff88);
+  min-width: 40px;
+  text-align: right;
+}
+
 /* Product set page: target dark two-column workspace with floating detail input. */
 .product-clone-page[data-tool="set"] {
   display: block;