feat: swipeable food sheet — Quick Add first, swipe for AI Chat

Replaced pill tab selector with swipeable TabView (.page style):
- Page 0: Quick Add (food search list) — shown first
- Page 1: AI Chat — swipe right to access
- Custom dot indicators replace the old pill tabs
- Swipe gesture between pages

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

ios/Platform/Platform/ContentView.swift

@@ -180,12 +180,13 @@ struct MainTabView: View {
 // MARK: - Assistant Sheet
 
 struct AssistantSheetView: View {
-    @State private var selectedMode = 0
+    @State private var selectedPage = 0
     var onFoodAdded: () -> Void = {}
 
     var body: some View {
         VStack(spacing: 0) {
-            VStack(spacing: 12) {
+            // Drag handle + title
+            VStack(spacing: 8) {
                 Capsule()
                     .fill(Color.textTertiary.opacity(0.3))
                     .frame(width: 36, height: 5)
@@ -195,41 +196,30 @@ struct AssistantSheetView: View {
                     .font(.headline)
                     .foregroundStyle(Color.textPrimary)
 
-                HStack(spacing: 4) {
-                    tabButton("AI Chat", icon: "sparkles", index: 0)
-                    tabButton("Quick Add", icon: "magnifyingglass", index: 1)
+                // Page indicator dots
+                HStack(spacing: 6) {
+                    Circle()
+                        .fill(selectedPage == 0 ? Color.accentWarm : Color.textTertiary.opacity(0.3))
+                        .frame(width: 7, height: 7)
+                    Circle()
+                        .fill(selectedPage == 1 ? Color.accentWarm : Color.textTertiary.opacity(0.3))
+                        .frame(width: 7, height: 7)
                 }
-                .padding(4)
-                .background(Color.textTertiary.opacity(0.08))
-                .clipShape(Capsule())
-                .padding(.horizontal, 40)
+                .padding(.bottom, 4)
             }
-            .padding(.bottom, 12)
             .background(Color.canvas)
 
-            if selectedMode == 0 {
-                AssistantChatView(onFoodAdded: onFoodAdded)
-            } else {
+            // Swipeable pages: Quick Add first, AI Chat second
+            TabView(selection: $selectedPage) {
                 FoodSearchView(isSheet: true, onFoodAdded: onFoodAdded)
+                    .tag(0)
+
+                AssistantChatView(onFoodAdded: onFoodAdded)
+                    .tag(1)
             }
+            .tabViewStyle(.page(indexDisplayMode: .never))
         }
         .background(Color.canvas)
         .presentationDetents([.large])
     }
-
-    private func tabButton(_ title: String, icon: String, index: Int) -> some View {
-        Button {
-            withAnimation(.easeInOut(duration: 0.2)) { selectedMode = index }
-        } label: {
-            HStack(spacing: 5) {
-                Image(systemName: icon).font(.caption2)
-                Text(title).font(.subheadline.weight(selectedMode == index ? .semibold : .regular))
-            }
-            .foregroundStyle(selectedMode == index ? Color.textPrimary : Color.textTertiary)
-            .padding(.horizontal, 16)
-            .padding(.vertical, 8)
-            .background(selectedMode == index ? Color.surfaceCard : Color.clear)
-            .clipShape(Capsule())
-        }
-    }
 }