Wire autocomplete into GifPickerHeader

Adds `autocomplete` prop (GifAutocompleteState) to GifPickerHeader,
restructures layout so suggestions render below the search bar, and
wires up keyboard navigation + ARIA attributes for the combobox pattern.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/features/gifPicker/components/GifPickerHeader.tsx

@@ -9,65 +9,87 @@ import * as TextField from '#/components/forms/TextField'
 import {ArrowLeft_Stroke2_Corner0_Rounded as Arrow} from '#/components/icons/Arrow'
 import {MagnifyingGlass_Stroke2_Corner0_Rounded as Search} from '#/components/icons/MagnifyingGlass'
 import {IS_WEB} from '#/env'
+import {
+  GIF_AUTOCOMPLETE_LISTBOX_ID,
+  GifAutocompleteSuggestions,
+  suggestionItemId,
+} from '#/features/gifPicker/components/GifAutocompleteSuggestions'
+import {type GifAutocompleteState} from '#/features/gifPicker/hooks/useGifAutocomplete'
 
 export function GifPickerHeader({
   inputRef,
   onChangeText,
   onClose,
   onEscape,
+  autocomplete,
 }: {
   inputRef: Ref<TextInput>
   onChangeText: (text: string) => void
   onClose: () => void
   onEscape: () => void
+  autocomplete: GifAutocompleteState
 }) {
   const {_} = useLingui()
   const t = useTheme()
   const {gtMobile} = useBreakpoints()
 
   return (
-    <View
-      style={[
-        native(a.pt_4xl),
-        a.relative,
-        a.mb_lg,
-        a.flex_row,
-        a.align_center,
-        !gtMobile && web(a.gap_md),
-        a.pb_sm,
-        t.atoms.bg,
-      ]}>
-      {!gtMobile && IS_WEB && (
-        <Button
-          size="small"
-          variant="ghost"
-          color="secondary"
-          shape="round"
-          onPress={onClose}
-          label={_(msg`Close GIF dialog`)}>
-          <ButtonIcon icon={Arrow} size="md" />
-        </Button>
-      )}
+    <View style={[native(a.pt_4xl), a.relative, a.mb_lg, a.pb_sm, t.atoms.bg]}>
+      <View style={[a.flex_row, a.align_center, !gtMobile && web(a.gap_md)]}>
+        {!gtMobile && IS_WEB && (
+          <Button
+            size="small"
+            variant="ghost"
+            color="secondary"
+            shape="round"
+            onPress={onClose}
+            label={_(msg`Close GIF dialog`)}>
+            <ButtonIcon icon={Arrow} size="md" />
+          </Button>
+        )}
 
-      <TextField.Root style={[!gtMobile && IS_WEB && a.flex_1]}>
-        <TextField.Icon icon={Search} />
-        <TextField.Input
-          label={_(msg`Search GIFs`)}
-          placeholder={_(msg`Search GIFs`)}
-          onChangeText={onChangeText}
-          returnKeyType="search"
-          clearButtonMode="while-editing"
-          inputRef={inputRef}
-          maxLength={50}
-          onKeyPress={({nativeEvent}) => {
-            if (nativeEvent.key === 'Escape') {
-              onEscape()
+        <TextField.Root style={[!gtMobile && IS_WEB && a.flex_1]}>
+          <TextField.Icon icon={Search} />
+          <TextField.Input
+            label={_(msg`Search GIFs`)}
+            placeholder={_(msg`Search GIFs`)}
+            onChangeText={onChangeText}
+            returnKeyType="search"
+            clearButtonMode="while-editing"
+            inputRef={inputRef}
+            maxLength={50}
+            onKeyPress={({nativeEvent}) => {
+              if (nativeEvent.key === 'Escape') {
+                if (!autocomplete.handleKeyDown('Escape')) {
+                  onEscape()
+                }
+              } else {
+                autocomplete.handleKeyDown(nativeEvent.key)
+              }
+            }}
+            // @ts-ignore web-only ARIA props
+            role={autocomplete.isVisible ? 'combobox' : undefined}
+            aria-controls={
+              autocomplete.isVisible ? GIF_AUTOCOMPLETE_LISTBOX_ID : undefined
             }
-          }}
-        />
-      </TextField.Root>
+            aria-expanded={autocomplete.isVisible}
+            aria-autocomplete={autocomplete.isVisible ? 'list' : undefined}
+            aria-activedescendant={
+              autocomplete.isVisible && autocomplete.activeIndex >= 0
+                ? suggestionItemId(autocomplete.activeIndex)
+                : undefined
+            }
+          />
+        </TextField.Root>
+      </View>
 
-      {/* future: tabs (Trending / Recents / Categories) render here */}
+      {autocomplete.isVisible && (
+        <GifAutocompleteSuggestions
+          suggestions={autocomplete.suggestions}
+          activeIndex={autocomplete.activeIndex}
+          onSelect={autocomplete.selectSuggestion}
+        />
+      )}
     </View>
   )
 }