feat(studio): 回退/重roll 与 R5 用户确认下一步

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/src/components/Studio/StudioRunPage.css

@@ -752,6 +752,43 @@
   cursor: not-allowed;
 }
 
+.studio-run-turn-actions__row {
+  display: flex;
+  gap: var(--spacing-xs);
+}
+
+.studio-run-turn-btn {
+  flex: 1;
+  padding: var(--spacing-sm) var(--spacing-md);
+  border: 1px solid var(--color-border-light);
+  border-radius: var(--radius-md);
+  background: var(--color-bg-secondary);
+  color: var(--color-text-primary);
+  font-size: 0.85rem;
+  font-weight: 500;
+  cursor: pointer;
+  transition: background 0.15s, border-color 0.15s;
+}
+
+.studio-run-turn-btn:hover:not(:disabled) {
+  background: var(--color-bg-tertiary);
+  border-color: var(--color-border);
+}
+
+.studio-run-turn-btn:disabled {
+  opacity: 0.45;
+  cursor: not-allowed;
+}
+
+.studio-run-turn-btn--reroll {
+  border-color: var(--color-accent);
+  color: var(--color-accent);
+}
+
+.studio-run-turn-btn--reroll:hover:not(:disabled) {
+  background: color-mix(in srgb, var(--color-accent) 12%, var(--color-bg-secondary));
+}
+
 .studio-run-stub-note {
   margin: 0;
   font-size: 0.65rem;