fix: Improve markdown formatting in release notes view

Add custom AttributedString extension to properly format markdown with correct spacing and header styles. This fixes the compressed appearance of release notes by adding proper line breaks between sections and applying appropriate font sizes to headers.

readeck/UI/Settings/ReleaseNotesView.swift

@@ -1,5 +1,46 @@
 import SwiftUI
 
+extension AttributedString {
+    init(styledMarkdown markdownString: String) throws {
+        var output = try AttributedString(
+            markdown: markdownString,
+            options: .init(
+                allowsExtendedAttributes: true,
+                interpretedSyntax: .full,
+                failurePolicy: .returnPartiallyParsedIfPossible
+            ),
+            baseURL: nil
+        )
+
+        for (intentBlock, intentRange) in output.runs[AttributeScopes.FoundationAttributes.PresentationIntentAttribute.self].reversed() {
+            guard let intentBlock = intentBlock else { continue }
+            for intent in intentBlock.components {
+                switch intent.kind {
+                case .header(level: let level):
+                    switch level {
+                    case 1:
+                        output[intentRange].font = .system(.title).bold()
+                    case 2:
+                        output[intentRange].font = .system(.title2).bold()
+                    case 3:
+                        output[intentRange].font = .system(.title3).bold()
+                    default:
+                        break
+                    }
+                default:
+                    break
+                }
+            }
+
+            if intentRange.lowerBound != output.startIndex {
+                output.characters.insert(contentsOf: "\n\n", at: intentRange.lowerBound)
+            }
+        }
+
+        self = output
+    }
+}
+
 struct ReleaseNotesView: View {
     @Environment(\.dismiss) private var dismiss
 
@@ -33,10 +74,7 @@ struct ReleaseNotesView: View {
     private func loadReleaseNotes() -> AttributedString? {
         guard let url = Bundle.main.url(forResource: "RELEASE_NOTES", withExtension: "md"),
               let markdownContent = try? String(contentsOf: url),
-              let attributedString = try? AttributedString(
+              let attributedString = try? AttributedString(styledMarkdown: markdownContent) else {
-                markdown: markdownContent,
-                options: .init(interpretedSyntax: .full)
-              ) else {
             return nil
         }
         return attributedString