longform: add estimated read time to longform preview

Display estimated reading time in minutes alongside word count for longform
articles. Uses standard 200 words per minute reading rate calculation.

Closes: https://github.com/damus-io/damus/issues/3492
Changelog-Added: Added estimated read time to longform preview
Signed-off-by: alltheseas

damus/Features/Events/Models/NoteContent.swift

@@ -381,6 +381,11 @@ struct LongformContent {
     let markdown: MarkdownContent
     let words: Int
 
+    /// Estimated reading time in minutes, based on average reading speed of 200 words per minute.
+    var estimatedReadTimeMinutes: Int {
+        return max(1, words / 200)
+    }
+
     init(_ markdown: String) {
         // Pre-process markdown to ensure images are block-level (have blank lines around them)
         // This prevents images from being parsed as inline within text paragraphs

damus/Features/Longform/Views/LongformPreview.swift

@@ -35,10 +35,17 @@ struct LongformPreviewBody: View {
         self._artifacts = ObservedObject(wrappedValue: state.events.get_cache_data(ev.id).artifacts_model)
     }
 
+    /// Formats word count for display.
     func Words(_ words: Int) -> Text {
         let wordCount = pluralizedString(key: "word_count", count: words)
         return Text(wordCount)
     }
+
+    /// Formats estimated read time for display.
+    func ReadTime(_ minutes: Int) -> Text {
+        let readTime = pluralizedString(key: "read_time", count: minutes)
+        return Text(readTime)
+    }
     
     var truncate: Bool {
         return options.contains(.truncate_content)
@@ -161,8 +168,14 @@ struct LongformPreviewBody: View {
             if case .loaded(let arts) = artifacts.state,
                case .longform(let longform) = arts
             {
-                Words(longform.words).font(.footnote)
-                    .padding([.horizontal, .bottom], 10)
+                HStack(spacing: 8) {
+                    ReadTime(longform.estimatedReadTimeMinutes)
+                    Text("·")
+                    Words(longform.words)
+                }
+                .font(.footnote)
+                .foregroundColor(.gray)
+                .padding([.horizontal, .bottom], 10)
             }
         }
         .frame(maxWidth: .infinity, alignment: .leading)

damus/en-US.lproj/Localizable.stringsdict

@@ -386,6 +386,22 @@
 			<string>%d Words</string>
 		</dict>
 	</dict>
+	<key>read_time</key>
+	<dict>
+		<key>NSStringLocalizedFormatKey</key>
+		<string>%#@MINUTES@</string>
+		<key>MINUTES</key>
+		<dict>
+			<key>NSStringFormatSpecTypeKey</key>
+			<string>NSStringPluralRuleType</string>
+			<key>NSStringFormatValueTypeKey</key>
+			<string>d</string>
+			<key>one</key>
+			<string>%d min read</string>
+			<key>other</key>
+			<string>%d min read</string>
+		</dict>
+	</dict>
 	<key>zap_notification_no_message</key>
 	<dict>
 		<key>NSStringLocalizedFormatKey</key>