ui: Longform Improvements

This patch improves longform previews by including the image title and tags.
In addition with minor UI touch ups.

Testing:

iPhone 15 Pro Max (17.3.1) Dark Mode:
https://v.nostr.build/9zgvv.mp4

iPhone SE (3rd generation) (16.4) Light Mode:
https://v.nostr.build/VwEKQ.mp4

Closes: https://github.com/damus-io/damus/issues/1742
Changelog-Added: Added title image and tags to longform events
Signed-off-by: ericholguin <ericholguin@apache.org>
Link: 20240415031636.68846-1-ericholguin@apache.org
Signed-off-by: William Casarin <jb55@jb55.com>

damus/Models/LongformEvent.swift

@@ -14,6 +14,7 @@ struct LongformEvent {
     var image: URL? = nil
     var summary: String? = nil
     var published_at: Date? = nil
+    var labels: [String]? = nil
     
     static func parse(from ev: NostrEvent) -> LongformEvent {
         var longform = LongformEvent(event: ev)
@@ -26,6 +27,10 @@ struct LongformEvent {
             case "summary": longform.summary = tag[1].string()
             case "published_at":
                 longform.published_at = Double(tag[1].string()).map { d in Date(timeIntervalSince1970: d) }
+            case "t":
+                if (longform.labels?.append(tag[1].string())) == nil {
+                    longform.labels = [tag[1].string()]
+                }
             default:
                 break
             }