New chat thread view

This commit changes the thread view to a new UX concept where children views of the selected view are now presented as chat bubbles, and the entire tree of conversation is shown flattened. New interactions, layout, and design changes have been introduced to revamp the user experience.

Testing
-------

Device: A mix of iPhone physical devices and simulator
iOS: A mix of iOS 17 versions
Damus: A mix of versions leading up to this one.
Coverage:
1. Unit tests are passing
2. A select few users have been using prototypes versions of this as their daily driver
3. Layout tested with an eclectic mix of threads
4. Posting new notes to the thread works
5. Clicking on reply quote view takes user to the mentioned message with a momentary visible highlight
6. Swipe actions work
7. Long press on chat bubbles works and shows emoji selector. Adding emoji sends the reaction
8. Clicking on notes selects them with an easy to follow transition

Known issues:
1. The text on the reply quote view occasionally appears to be off-center (in about 10% of occurrences). The cause is still unknown
2. Long press will still show the emoji keyboard even if user is on "onlyzaps" mode
3. Quoted events are not rendered on chat bubbles. When user posts a quoted event with no text, that could lead to confusion

Closes: https://github.com/damus-io/damus/issues/1126
Changelog-Added: Completely new threads experience that is easier and more pleasant to use
Signed-off-by: Daniel D’Aquino <daniel@daquino.me>

damus/Util/EventCache.swift

@@ -97,13 +97,13 @@ class EventCache {
     // TODO: remove me and change code to use ndb directly
     private let ndb: Ndb
     private var events: [NoteId: NostrEvent] = [:]
-    private var replies = ReplyMap()
     private var cancellable: AnyCancellable?
     private var image_metadata: [String: ImageMetadataState] = [:] // lowercased URL key
     private var event_data: [NoteId: EventData] = [:]
+    var replies = ReplyMap()
 
     //private var thread_latest: [String: Int64]
-    
+
     init(ndb: Ndb) {
         self.ndb = ndb
         cancellable = NotificationCenter.default.publisher(
@@ -187,7 +187,7 @@ class EventCache {
             replies.add(id: reply, reply_id: ev.id)
         }
     }
-    
+
     func child_events(event: NostrEvent) -> [NostrEvent] {
         guard let xs = replies.lookup(event.id) else {
             return []

damus/Util/Extensions/VectorMath.swift

@@ -0,0 +1,27 @@
+//
+//  VectorMath.swift
+//  damus
+//
+//  Created by Daniel D’Aquino on 2024-06-17.
+//
+
+import Foundation
+
+extension CGPoint {
+    /// Summing a vector to a point
+    static func +(lhs: CGPoint, rhs: CGVector) -> CGPoint {
+        return CGPoint(x: lhs.x + rhs.dx, y: lhs.y + rhs.dy)
+    }
+    
+    /// Subtracting a vector from a point
+    static func -(lhs: CGPoint, rhs: CGVector) -> CGPoint {
+        return CGPoint(x: lhs.x - rhs.dx, y: lhs.y - rhs.dy)
+    }
+}
+
+extension CGVector {
+    /// Multiplying a vector by a scalar
+    static func *(lhs: CGVector, rhs: CGFloat) -> CGVector {
+        return CGVector(dx: lhs.dx * rhs, dy: lhs.dy * rhs)
+    }
+}

damus/Util/Router.swift

@@ -93,7 +93,8 @@ enum Route: Hashable {
         case .FirstAidSettings(settings: let settings):
             FirstAidSettingsView(damus_state: damusState, settings: settings)
         case .Thread(let thread):
-            ThreadView(state: damusState, thread: thread)
+            ChatroomThreadView(damus: damusState, thread: thread)
+            //ThreadView(state: damusState, thread: thread)
         case .Reposts(let reposts):
             RepostsView(damus_state: damusState, model: reposts)
         case .QuoteReposts(let quote_reposts):