feat: add reader keyboard support on iOS and tvOS (#731)

## Problem
Reader keyboard support was limited to macOS even though iPad, iPhone,
and Apple TV can all be used with external keyboards. The help overlay
also shared settings across reader types, and the initial UIKit
responder handling introduced two iOS regressions: sheet presentation
could trigger AttributeGraph cycle warnings, and EPUB keyboard shortcuts
could stop responding after toggling controls.

## Approach
This PR introduces shared reader keyboard command models and routes iOS
and tvOS key events through a UIKit bridge while keeping the existing
macOS command integration. The keyboard help overlay is available across
supported reader platforms, auto-shows only when appropriate, and uses
per-reader configuration where needed. On iOS, responder updates are
deferred off the SwiftUI update path and then refreshed asynchronously
so the reader can recover keyboard focus without reintroducing the cycle
warning.

## Scope
- Add iOS and tvOS keyboard shortcut support for DIVINA reader
navigation and controls
- Extend the keyboard help overlay and auto-show behavior across DIVINA,
EPUB, and PDF readers
- Add independent EPUB and PDF keyboard help preferences while
preserving DIVINA settings
- Refactor reader command state and handlers into platform-neutral types
- Avoid iOS AttributeGraph cycles by deferring UIKit first responder
changes outside SwiftUI updates
- Restore EPUB keyboard shortcut responsiveness after toggling controls
on iOS
- Bump build version to 399

Author: everpcpc

KMReader.xcodeproj/project.pbxproj

@@ -438,7 +438,7 @@
 				"CODE_SIGN_ENTITLEMENTS[sdk=macosx*]" = "KMReader/KMReader-macOS.entitlements";
 				CODE_SIGN_IDENTITY = "Apple Development";
 				CODE_SIGN_STYLE = Automatic;
-				CURRENT_PROJECT_VERSION = 398;
+				CURRENT_PROJECT_VERSION = 399;
 				DEVELOPMENT_TEAM = M777UHWZA4;
 				ENABLE_APP_SANDBOX = YES;
 				ENABLE_HARDENED_RUNTIME = YES;
@@ -496,7 +496,7 @@
 				"CODE_SIGN_ENTITLEMENTS[sdk=macosx*]" = "KMReader/KMReader-macOS.entitlements";
 				CODE_SIGN_IDENTITY = "Apple Distribution";
 				CODE_SIGN_STYLE = Manual;
-				CURRENT_PROJECT_VERSION = 398;
+				CURRENT_PROJECT_VERSION = 399;
 				DEVELOPMENT_TEAM = "";
 				"DEVELOPMENT_TEAM[sdk=appletvos*]" = M777UHWZA4;
 				"DEVELOPMENT_TEAM[sdk=iphoneos*]" = M777UHWZA4;
@@ -556,7 +556,7 @@
 				CODE_SIGN_ENTITLEMENTS = KMReaderWidgets/KMReaderWidgets.entitlements;
 				CODE_SIGN_IDENTITY = "Apple Development";
 				CODE_SIGN_STYLE = Automatic;
-				CURRENT_PROJECT_VERSION = 398;
+				CURRENT_PROJECT_VERSION = 399;
 				DEVELOPMENT_TEAM = M777UHWZA4;
 				GENERATE_INFOPLIST_FILE = YES;
 				INFOPLIST_FILE = KMReaderWidgets/Info.plist;
@@ -590,7 +590,7 @@
 				CODE_SIGN_IDENTITY = "Apple Distribution";
 				"CODE_SIGN_IDENTITY[sdk=iphoneos*]" = "iPhone Distribution";
 				CODE_SIGN_STYLE = Manual;
-				CURRENT_PROJECT_VERSION = 398;
+				CURRENT_PROJECT_VERSION = 399;
 				DEVELOPMENT_TEAM = "";
 				"DEVELOPMENT_TEAM[sdk=iphoneos*]" = M777UHWZA4;
 				GENERATE_INFOPLIST_FILE = YES;

KMReader/Core/Storage/AppConfig.swift

@@ -545,6 +545,18 @@ enum AppConfig {
     }
   }
 
+  static nonisolated var epubShowKeyboardHelpOverlay: Bool {
+    get {
+      if UserDefaults.standard.object(forKey: "epubShowKeyboardHelpOverlay") != nil {
+        return UserDefaults.standard.bool(forKey: "epubShowKeyboardHelpOverlay")
+      }
+      return true
+    }
+    set {
+      UserDefaults.standard.set(newValue, forKey: "epubShowKeyboardHelpOverlay")
+    }
+  }
+
   static nonisolated var enableReaderLiveActivity: Bool {
     get {
       if UserDefaults.standard.object(forKey: "enableReaderLiveActivity") != nil {

KMReader/Core/Storage/LiveTextManager.swift

@@ -5,15 +5,15 @@
 
 import Foundation
 
-#if !os(tvOS)
+#if os(iOS) || os(macOS)
   import VisionKit
 #endif
 
 @MainActor
 class LiveTextManager {
   static let shared = LiveTextManager()
 
-  #if !os(tvOS)
+  #if os(iOS) || os(macOS)
     let analyzer = ImageAnalyzer()
   #endif
 

KMReader/Features/Auth/ViewModels/AuthViewModel.swift

@@ -297,7 +297,7 @@ class AuthViewModel {
     await SSEService.shared.connect()
 
     WidgetDataService.refreshWidgetData()
-    #if !os(tvOS)
+    #if os(iOS) || os(macOS)
       SpotlightIndexService.removeAllItems()
       SpotlightIndexService.indexAllDownloadedBooks(instanceId: finalInstanceId)
     #endif

KMReader/Features/Auth/Views/LoginView.swift

@@ -209,7 +209,7 @@ struct LoginView: View {
         .frame(maxWidth: .infinity)
         .padding(.vertical, 10)
       }
-      #if !os(tvOS)
+      #if os(iOS) || os(macOS)
         .frame(maxWidth: 360)
       #endif
       .frame(maxWidth: .infinity, alignment: .center)

KMReader/Features/Book/Views/BookDetailView.swift

@@ -88,7 +88,7 @@ struct BookDetailView: View {
       url: KomgaWebLinkBuilder.book(serverURL: current.serverURL, bookId: bookId),
       scope: .browse
     )
-    #if !os(tvOS)
+    #if os(iOS) || os(macOS)
       .toolbar {
         ToolbarItem(placement: .automatic) {
           bookToolbarContent
@@ -239,7 +239,7 @@ struct BookDetailView: View {
   @ViewBuilder
   private var bookToolbarContent: some View {
     HStack {
-      #if !os(tvOS)
+      #if os(iOS) || os(macOS)
         if let shareURL {
           ShareLink(item: shareURL, subject: Text(navigationTitle)) {
             Image(systemName: "square.and.arrow.up")

KMReader/Features/Browse/Views/BrowseView.swift

@@ -148,7 +148,7 @@ struct BrowseView: View {
     .inlineNavigationBarTitle(title)
     .animation(.default, value: librarySelection)
     .searchable(text: $searchQuery)
-    #if !os(tvOS)
+    #if os(iOS) || os(macOS)
       .toolbar {
         if librarySelection == nil {
           #if os(macOS)

KMReader/Features/Browse/Views/SavedFiltersView.swift

@@ -83,7 +83,7 @@ struct SavedFiltersView: View {
       }
       .adaptiveButtonStyle(.plain)
     }
-    #if !os(tvOS)
+    #if os(iOS) || os(macOS)
       .swipeActions(edge: .trailing, allowsFullSwipe: false) {
         Button(role: .destructive) {
           deleteFilter(filter)

KMReader/Features/Collection/Views/CollectionDetailView.swift

@@ -90,7 +90,7 @@ struct CollectionDetailView: View {
     } message: {
       Text("This will permanently delete \(collection?.name ?? "this collection") from Komga.")
     }
-    #if !os(tvOS)
+    #if os(iOS) || os(macOS)
       .toolbar {
         ToolbarItem(placement: .automatic) {
           collectionToolbarContent

KMReader/Features/Dashboard/Views/DashboardView.swift

@@ -321,7 +321,7 @@ struct DashboardView: View {
         }
       }
     }
-    #if !os(tvOS)
+    #if os(iOS) || os(macOS)
       .toolbar {
         #if os(macOS)
           ToolbarItem(placement: .navigation) {