feat: calorie tap → fitness, confetti on food add, reduce dashboard padding

- Calorie widget taps switches to Fitness tab
- After adding food: dismiss sheet, switch to Fitness, confetti animation
- Confetti: emoji particles falling + checkmark + haptic feedback
- Dashboard top padding reduced from 60pt to 16pt
- HomeView accepts selectedTab binding

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

ios/Platform/Platform/Features/Assistant/AssistantChatView.swift

@@ -3,6 +3,7 @@ import PhotosUI
 
 struct AssistantChatView: View {
     @State private var vm = AssistantViewModel()
+    var onFoodAdded: (() -> Void)?
 
     var body: some View {
         VStack(spacing: 0) {
@@ -113,6 +114,13 @@ struct AssistantChatView: View {
         .onChange(of: vm.selectedPhoto) {
             Task { await vm.handlePhotoSelection() }
         }
+        .onChange(of: vm.applied) {
+            if vm.applied {
+                DispatchQueue.main.asyncAfter(deadline: .now() + 0.5) {
+                    onFoodAdded?()
+                }
+            }
+        }
     }
 
     // MARK: - Chat Bubble

ios/Platform/Platform/Features/Home/HomeView.swift

@@ -4,8 +4,8 @@ import PhotosUI
 struct HomeView: View {
     @Environment(AuthManager.self) private var auth
     @State private var vm = HomeViewModel()
-    @State private var showAssistant = false
     @State private var ringAnimated = false
+    @Binding var selectedTab: Int
 
     var body: some View {
         ZStack {
@@ -54,12 +54,15 @@ struct HomeView: View {
                         }
                     }
                     .padding(.horizontal)
-                    .padding(.top, 60)
+                    .padding(.top, 16)
 
-                    // Widget grid — half width
+                    // Widget grid — half width, tap to go to fitness
                     HStack(spacing: 12) {
-                        calorieWidget
-                        // Future widget placeholder — invisible spacer
+                        Button { selectedTab = 1 } label: {
+                            calorieWidget
+                        }
+                        .buttonStyle(.plain)
+
                         Color.clear
                     }
                     .padding(.horizontal)