feat(HAI-069): double flash animation duration from 700ms to 1400ms

- Update useFlashOnIncrease default duration from 700ms to 1400ms
- Update CSS count-flash-bg animation duration to 1400ms
- Update test assertions to match new 1400ms duration

packages/dashboard/app/hooks/useFlashOnIncrease.test.ts

@@ -28,7 +28,7 @@ describe("useFlashOnIncrease", () => {
 
   it("resets flashing after duration", () => {
     const { result, rerender } = renderHook(
-      ({ count }) => useFlashOnIncrease(count, 700),
+      ({ count }) => useFlashOnIncrease(count, 1400),
       { initialProps: { count: 3 } },
     );
 
@@ -36,7 +36,7 @@ describe("useFlashOnIncrease", () => {
     expect(result.current).toBe(true);
 
     act(() => {
-      vi.advanceTimersByTime(700);
+      vi.advanceTimersByTime(1400);
     });
     expect(result.current).toBe(false);
   });

packages/dashboard/app/hooks/useFlashOnIncrease.ts

@@ -6,10 +6,10 @@ import { useRef, useState, useEffect } from "react";
  *
  * - Does NOT flash on initial render (only on subsequent increases).
  * - Does NOT flash when count decreases or stays the same.
- * - Resets after `duration` ms (default 700ms).
+ * - Resets after `duration` ms (default 1400ms).
  * - Cleans up timers on unmount.
  */
-export function useFlashOnIncrease(count: number, duration = 700): boolean {
+export function useFlashOnIncrease(count: number, duration = 1400): boolean {
   const prevRef = useRef<number | null>(null);
   const [flashing, setFlashing] = useState(false);
   const timerRef = useRef<ReturnType<typeof setTimeout> | null>(null);

packages/dashboard/app/styles.css

@@ -168,7 +168,7 @@ html, body {
 }
 
 .column-count.count-flash {
-  animation: count-flash-bg 700ms ease-out;
+  animation: count-flash-bg 1400ms ease-out;
 }
 
 .column-desc {