perf(ui): optimize transition timing and keyboard viewport coordination

Adjust the global section overlay transition duration and easing for a
snappier feel. Update the viewport coordinator to use a more responsive
keyboard threshold and provide a fallback default height to ensure
consistent lifting behavior when the last known height is insufficient.

src/app/globals.css

@@ -351,7 +351,7 @@ body.section-overlay-open .app-shell {
     calc(var(--question-lift-y, 0px) * -1),
     0
   );
-  transition: transform 340ms cubic-bezier(0.22, 1, 0.36, 1);
+  transition: transform 200ms cubic-bezier(0.16, 1, 0.3, 1);
   will-change: transform;
 }
 

src/components/Componentes/question-viewport-coordinator.ts

@@ -3,7 +3,8 @@
 import { useEffect } from "react";
 import { viewPaddingsBridge } from "@/lib/view-paddings";
 
-const KEYBOARD_THRESHOLD = 80;
+const KEYBOARD_THRESHOLD = 40;
+const DEFAULT_KEYBOARD_HEIGHT = 280;
 const QUESTION_GAP = 16;
 const LIFT_VARIABLE = "--question-lift-y";
 
@@ -194,10 +195,13 @@ export function useQuestionViewportCoordinator() {
       if (!isActiveQuestionKeyboardInput(event.target)) return;
       activeQuestionInput = event.target;
 
-      // Start with the last known keyboard geometry so lifting begins in the
-      // same frame as focus; Flutter then replaces it with the exact height.
-      if (!keyboardVisible && lastKeyboardHeight > KEYBOARD_THRESHOLD) {
-        keyboardHeight = lastKeyboardHeight;
+      // Start with the last known keyboard geometry or standard default so lifting begins in the
+      // same frame as focus; Flutter/visualViewport then replaces it with the exact height.
+      if (!keyboardVisible) {
+        keyboardHeight =
+          lastKeyboardHeight > KEYBOARD_THRESHOLD
+            ? lastKeyboardHeight
+            : DEFAULT_KEYBOARD_HEIGHT;
         keyboardVisible = true;
       }
       scheduleLiftUpdate();