feat: auto-focus search field when Quick Add opens in sheet

Keyboard appears automatically when opening Quick Add from the
food assistant sheet. 300ms delay lets the sheet animation finish
first so the keyboard doesn't interfere with the presentation.

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

ios/Platform/Platform/Features/Fitness/Views/FoodSearchView.swift

@@ -5,6 +5,7 @@ struct FoodSearchView: View {
     var onFoodAdded: (() -> Void)?
     @State private var vm = FoodSearchViewModel()
     @State private var selectedFood: Food?
+    @FocusState private var searchFocused: Bool
 
     var body: some View {
         VStack(spacing: 0) {
@@ -15,6 +16,7 @@ struct FoodSearchView: View {
                 TextField("Search foods...", text: $vm.searchText)
                     .textFieldStyle(.plain)
                     .autocorrectionDisabled()
+                    .focused($searchFocused)
                 if !vm.searchText.isEmpty {
                     Button {
                         vm.searchText = ""
@@ -44,6 +46,11 @@ struct FoodSearchView: View {
         .background(Color.canvas)
         .task {
             await vm.loadInitial()
+            if isSheet {
+                // Small delay so sheet animation completes first
+                try? await Task.sleep(for: .milliseconds(300))
+                searchFocused = true
+            }
         }
         .onChange(of: vm.searchText) {
             vm.search()