feat: center selected item in viewport when dialog opens or after bookmark

- Add 'center' parameter to moveTo() function
- Pass center=true from effect (dialog open) and scrollToValue (bookmark toggle)
- Keyboard navigation still uses edge-scroll behavior for smooth UX

Author: ariane-emory

packages/opencode/src/cli/cmd/tui/ui/dialog-select.tsx

@@ -98,11 +98,11 @@ export function DialogSelect<T>(props: DialogSelectProps<T>) {
     on([() => store.filter, () => props.current], ([filter, current]) => {
       setTimeout(() => {
         if (filter.length > 0) {
-          moveTo(0)
+          moveTo(0, true)
         } else if (current) {
           const currentIndex = flat().findIndex((opt) => isDeepEqual(opt.value, current))
           if (currentIndex >= 0) {
-            moveTo(currentIndex)
+            moveTo(currentIndex, true)
           }
         }
       }, 0)
@@ -117,7 +117,7 @@ export function DialogSelect<T>(props: DialogSelectProps<T>) {
     moveTo(next)
   }
 
-  function moveTo(next: number) {
+  function moveTo(next: number, center = false) {
     setStore("selected", next)
     props.onMove?.(selected()!)
     if (!scroll) return
@@ -126,13 +126,18 @@ export function DialogSelect<T>(props: DialogSelectProps<T>) {
     })
     if (!target) return
     const y = target.y - scroll.y
-    if (y >= scroll.height) {
-      scroll.scrollBy(y - scroll.height + 1)
-    }
-    if (y < 0) {
-      scroll.scrollBy(y)
-      if (isDeepEqual(flat()[0].value, selected()?.value)) {
-        scroll.scrollTo(0)
+    if (center) {
+      const centerOffset = Math.floor(scroll.height / 2)
+      scroll.scrollBy(y - centerOffset)
+    } else {
+      if (y >= scroll.height) {
+        scroll.scrollBy(y - scroll.height + 1)
+      }
+      if (y < 0) {
+        scroll.scrollBy(y)
+        if (isDeepEqual(flat()[0].value, selected()?.value)) {
+          scroll.scrollTo(0)
+        }
       }
     }
   }
@@ -176,7 +181,7 @@ export function DialogSelect<T>(props: DialogSelectProps<T>) {
     scrollToValue(value: T) {
       const index = flat().findIndex((opt) => isDeepEqual(opt.value, value))
       if (index >= 0) {
-        moveTo(index)
+        moveTo(index, true)
       }
     },
   }