feat(views): refine navigation progress bar with brand color and glow (MUL-2269) (#2681)

* feat(views): refine navigation progress bar with brand color and glow (MUL-2269)

The previous 1px bg-primary bar read as near-black on light theme and
snapped on/off in a single frame, which felt abrupt despite being a small
visual element. Switch to a 2px brand-colored sweep with right-edge glow,
slower 1.4s cubic-bezier easing, and a 200ms fade-out so completion
doesn't pop.

- Container: h-px → h-0.5 (2px); always mounted with opacity-driven fade
- Bar: bg-primary → bg-brand + two-layer box-shadow glow via color-mix
- Keyframe: 1.1s ease-in-out → 1.4s cubic-bezier(0.4, 0, 0.2, 1)

Zero new design tokens (reuses existing --brand) and zero tailwind config
changes. Desktop unaffected — same component, same prefetch=no-op path.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Co-authored-by: multica-agent <github@multica.ai>

* fix(views): unmount nav progress sweep when hidden (MUL-2269)

Hiding the bar with opacity-0 left the inner element's `infinite` keyframe
animation running on every dashboard page, defeating the perceived-perf goal.
Mount the sweep only while navigating, plus the 200ms fade tail (unmount on
opacity transitionend), so nothing animates while hidden.

Co-authored-by: multica-agent <github@multica.ai>

---------

Co-authored-by: Claude Opus 4.7 <noreply@anthropic.com>
Co-authored-by: multica-agent <github@multica.ai>

packages/ui/styles/base.css

@@ -114,17 +114,18 @@
   animation: chat-text-shimmer 2.5s linear infinite;
 }
 
-/* Navigation progress bar: 1px brand-tinted indeterminate sweep that shows
- * across the top of the dashboard while a transition-wrapped push/replace is
- * committing. Driven by useIsNavigating(); independent of the actual network,
- * so it disappears the moment React commits the new route. */
+/* Navigation progress bar: 2px brand-colored indeterminate sweep with a
+ * right-edge glow that shows across the top of the dashboard while a
+ * transition-wrapped push/replace is committing. Driven by useIsNavigating();
+ * independent of the actual network, so it disappears the moment React commits
+ * the new route. */
 @keyframes nav-progress-sweep {
   0% { transform: translateX(-100%); }
   100% { transform: translateX(100%); }
 }
 
 .animate-nav-progress-sweep {
-  animation: nav-progress-sweep 1.1s ease-in-out infinite;
+  animation: nav-progress-sweep 1.4s cubic-bezier(0.4, 0, 0.2, 1) infinite;
 }
 
 /* Border beam: a brand-tinted highlight sweeps continuously around the

packages/views/layout/navigation-progress.tsx

@@ -1,19 +1,45 @@
 "use client";
 
+import { useEffect, useState } from "react";
+
 import { useIsNavigating } from "../navigation";
 
-// 1px top-of-content progress bar shown while a transition-wrapped
+// 2px top-of-content progress bar shown while a transition-wrapped
 // push/replace is mid-flight. Indeterminate by design — we don't know
 // when the next route will commit, just that it's coming.
+//
+// The container stays mounted so it can fade out over 200ms instead of
+// vanishing in one frame. The inner sweep is mounted only while navigating
+// (plus the fade-out tail); leaving its `infinite` keyframe animation
+// running while hidden would burn paints on every dashboard view.
 export function NavigationProgress() {
   const isNavigating = useIsNavigating();
-  if (!isNavigating) return null;
+  const [renderSweep, setRenderSweep] = useState(false);
+
+  useEffect(() => {
+    if (isNavigating) setRenderSweep(true);
+  }, [isNavigating]);
+
   return (
     <div
       aria-hidden
-      className="pointer-events-none absolute inset-x-0 top-0 z-50 h-px overflow-hidden"
+      data-visible={isNavigating ? "true" : "false"}
+      onTransitionEnd={(event) => {
+        if (event.propertyName === "opacity" && !isNavigating) {
+          setRenderSweep(false);
+        }
+      }}
+      className="pointer-events-none absolute inset-x-0 top-0 z-50 h-0.5 overflow-hidden opacity-0 transition-opacity duration-200 data-[visible=true]:opacity-100"
     >
-      <div className="h-full w-1/3 animate-nav-progress-sweep bg-primary" />
+      {renderSweep && (
+        <div
+          className="h-full w-1/3 animate-nav-progress-sweep bg-brand"
+          style={{
+            boxShadow:
+              "0 0 8px color-mix(in oklab, var(--brand) 60%, transparent), 0 0 2px color-mix(in oklab, var(--brand) 80%, transparent)",
+          }}
+        />
+      )}
     </div>
   );
 }