Replace TipKit with custom themed tips modal system

- Add TipModalView with gradient header, themed styling, and spring animations
- Create FeelsTipsManager with global toggle, session tracking, and persistence
- Define FeelsTip protocol and convert all 7 tips to new system
- Add convenience view modifiers (.customizeLayoutTip(), .aiInsightsTip(), etc.)
- Remove TipKit dependency from all views
- Add Tips Preview debug screen in Settings to test all tip modals
- Update documentation for new custom tips system

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Shared/Views/CustomizeView/CustomizeView.swift

@@ -7,7 +7,6 @@
 
 import SwiftUI
 import StoreKit
-import TipKit
 
 // MARK: - Customize Content View (for use in SettingsTabView)
 struct CustomizeContentView: View {
@@ -20,10 +19,6 @@ struct CustomizeContentView: View {
     var body: some View {
         ScrollView {
             VStack(spacing: 24) {
-                // Customize tip
-                TipView(CustomizeLayoutTip())
-                    .tipBackground(Color(.secondarySystemBackground))
-
                 // QUICK THEMES
                 SettingsSection(title: "Quick Start") {
                     Button(action: { showThemePicker = true }) {
@@ -137,6 +132,7 @@ struct CustomizeContentView: View {
         .onAppear(perform: {
             EventLogger.log(event: "show_customize_view")
         })
+        .customizeLayoutTip()
     }
 }