fix(app): remove release-notes WebView bottom safe-area gap

Extend the sheet WebView under the home indicator, keep scroll insets cleared after navigation, and neutralize remote page safe-area bottom padding in-app.

OSGKeyboard/Views/Components/RemoteWebView.swift

@@ -1,7 +1,7 @@
 // RemoteWebView.swift
 // OSGKeyboard · Main App
 //
-// In-app WKWebView for remote HTTPS pages (e.g. GitHub Issues).
+// In-app WKWebView for remote HTTPS pages (e.g. GitHub Issues, release notes).
 
 import SwiftUI
 import WebKit
@@ -9,9 +9,12 @@ import WebKit
 struct RemoteWebView: UIViewRepresentable {
     let url: URL
     @Binding var isLoading: Bool
+    /// When true, strip page `env(safe-area-inset-*)` bottom padding after load
+    /// (sheets already lay out above the home indicator).
+    var neutralizeSafeAreaPadding: Bool = false
 
     func makeCoordinator() -> Coordinator {
-        Coordinator(isLoading: $isLoading)
+        Coordinator(isLoading: $isLoading, neutralizeSafeAreaPadding: neutralizeSafeAreaPadding)
     }
 
     func makeUIView(context: Context) -> WKWebView {
@@ -19,11 +22,7 @@ struct RemoteWebView: UIViewRepresentable {
         webView.isOpaque = false
         webView.backgroundColor = .clear
         webView.scrollView.backgroundColor = .clear
-        // Sheet / NavigationStack already lays out inside the safe area.
-        // Automatic adjustment would add a second bottom inset and leave a dead band.
-        webView.scrollView.contentInsetAdjustmentBehavior = .never
-        webView.scrollView.contentInset = .zero
-        webView.scrollView.scrollIndicatorInsets = .zero
+        Self.applyScrollInsets(webView)
         webView.navigationDelegate = context.coordinator
         context.coordinator.loadedURL = url
         webView.load(URLRequest(url: url))
@@ -31,33 +30,66 @@ struct RemoteWebView: UIViewRepresentable {
     }
 
     func updateUIView(_ uiView: WKWebView, context: Context) {
+        context.coordinator.neutralizeSafeAreaPadding = neutralizeSafeAreaPadding
+        Self.applyScrollInsets(uiView)
         guard context.coordinator.loadedURL != url else { return }
         context.coordinator.loadedURL = url
         uiView.load(URLRequest(url: url))
     }
 
+    /// Kill automatic safe-area insets that leave a dead band under the page.
+    static func applyScrollInsets(_ webView: WKWebView) {
+        let scroll = webView.scrollView
+        scroll.contentInsetAdjustmentBehavior = .never
+        scroll.contentInset = .zero
+        scroll.scrollIndicatorInsets = .zero
+        scroll.automaticallyAdjustsScrollIndicatorInsets = false
+    }
+
     final class Coordinator: NSObject, WKNavigationDelegate {
         @Binding var isLoading: Bool
         var loadedURL: URL?
+        var neutralizeSafeAreaPadding: Bool
 
-        init(isLoading: Binding<Bool>) {
+        init(isLoading: Binding<Bool>, neutralizeSafeAreaPadding: Bool) {
             _isLoading = isLoading
+            self.neutralizeSafeAreaPadding = neutralizeSafeAreaPadding
         }
 
         func webView(_ webView: WKWebView, didStartProvisionalNavigation navigation: WKNavigation!) {
             isLoading = true
+            RemoteWebView.applyScrollInsets(webView)
         }
 
         func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
             isLoading = false
+            RemoteWebView.applyScrollInsets(webView)
+            guard neutralizeSafeAreaPadding else { return }
+            // Remote HTML may still use env(safe-area-inset-bottom); neutralize in-app.
+            webView.evaluateJavaScript(
+                """
+                (function () {
+                  var s = document.getElementById('osg-webview-safe-area-fix');
+                  if (!s) {
+                    s = document.createElement('style');
+                    s.id = 'osg-webview-safe-area-fix';
+                    document.head.appendChild(s);
+                  }
+                  s.textContent = 'html{height:100%;} body{min-height:100%;padding-bottom:24px!important;}';
+                })();
+                """,
+                completionHandler: nil
+            )
         }
 
         func webView(_ webView: WKWebView, didFail navigation: WKNavigation!, withError error: Error) {
             isLoading = false
+            RemoteWebView.applyScrollInsets(webView)
         }
 
         func webView(_ webView: WKWebView, didFailProvisionalNavigation navigation: WKNavigation!, withError error: Error) {
             isLoading = false
+            RemoteWebView.applyScrollInsets(webView)
         }
     }
 }

OSGKeyboard/Views/ReleaseNotesSheet.swift

@@ -36,7 +36,16 @@ struct ReleaseNotesSheet: View {
                     colorScheme: resolvedColorScheme
                 ) {
                     ZStack {
-                        RemoteWebView(url: url, isLoading: $isLoading)
+                        // Fill the sheet body edge-to-edge (including home-indicator
+                        // band). WKWebView otherwise sits above a blank safe-area strip.
+                        RemoteWebView(
+                            url: url,
+                            isLoading: $isLoading,
+                            neutralizeSafeAreaPadding: true
+                        )
+                        .frame(maxWidth: .infinity, maxHeight: .infinity)
+                        .ignoresSafeArea(edges: .bottom)
+
                         if isLoading {
                             ProgressView()
                                 .tint(palette.accent)
@@ -52,6 +61,7 @@ struct ReleaseNotesSheet: View {
                     )
                 }
             }
+            .frame(maxWidth: .infinity, maxHeight: .infinity)
             .background(palette.background.ignoresSafeArea())
             .navigationTitle(AppL10n.string("releaseNotes.title", language: language))
             .navigationBarTitleDisplayMode(.inline)
@@ -63,6 +73,9 @@ struct ReleaseNotesSheet: View {
                 }
             }
         }
+        // Force full-height sheet so the web view isn't clipped under a mid detent.
+        .presentationDetents([.large])
+        .presentationDragIndicator(.visible)
         // Sheet can drop WindowGroup environment; re-assert language + appearance.
         .environment(\.locale, language.swiftUILocale)
         .preferredColorScheme(appearance.colorScheme)