Fix iPad share sheet covering QR code (#539)

* Fix iPad share sheet covering QR code (#539)

The share sheet popover on iPad was appearing centered over the QR code, covering it entirely.

Now the popover anchors to the bottom of the source view with an upward arrow, so the QR code remains visible. Fixes both ConversationShareView and AutoShareSheetView.

Stacked on #538.

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> [!NOTE]
> ### Anchor iPad share sheet popover to bottom to avoid covering QR code
> - Updates `UIActivityViewController` popover configuration in [ConversationShareView.swift](https://github.com/xmtplabs/convos-ios/pull/539/files#diff-0b61b1a39f237dac83028d3a0b4a1ba744cb88f15934fd101e4b1f3a68cbbec9) and [AutoShareSheetView.swift](https://github.com/xmtplabs/convos-ios/pull/539/files#diff-621c78e434aee4ede856c47b009aefd7589beefb5c9aaf92b90c0ec022b5bf6a) to anchor to the bottom of the view with an upward arrow instead of centering without arrows
> - Adjusts message attachment placeholder alignment in [MessagesGroupItemView.swift](https://github.com/xmtplabs/convos-ios/pull/539/files#diff-34b33cae925fe553d357af97d04319b8de2de329c1903afe72c915e36aa98774) to align trailing for outgoing messages and leading for incoming messages in regular width, with side padding
>
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> <sup><a href="https://app.macroscope.com">Macroscope</a> summarized 37fceeb.</sup>
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* Add bottom padding to quickname sheet on iPad (#540)

* Fix iPad photo alignment: left-align incoming, right-align outgoing

Photos on iPad were center-aligned. Now incoming photos align to the
leading edge and outgoing photos align to the trailing edge, with
step4x (16pt) padding on the respective side. Applies to loaded
photos, loading placeholders, and error placeholders.

* Fix iPad share sheet covering QR code

Position the share sheet popover at the bottom of the source view
with an upward arrow direction, so it appears below the QR code
instead of covering it. Fixes both ConversationShareView and
AutoShareSheetView.

* Reduce QR code size on iPhone to avoid share sheet overlap

Increase shareSheetFraction from 0.45 to 0.55 so the QR code sizes
itself smaller, leaving room for the share sheet on iPhone.

* Add bottom padding to quickname sheet on iPad

Match the bottom padding used by FeatureInfoSheet: step10x on iPad
(regular width), step6x on iPhone.

---------

Co-authored-by: yewreeka <7864+yewreeka@users.noreply.github.com>

Author: yewreeka

Convos/Conversation Detail/Conversation Detail Drawer/WhatIsQuicknameView.swift

@@ -4,6 +4,7 @@ struct WhatIsQuicknameView: View {
     let onContinue: () -> Void
 
     @State private var quicknameSettings: QuicknameSettingsViewModel = .shared
+    @Environment(\.horizontalSizeClass) private var horizontalSizeClass: UserInterfaceSizeClass?
 
     var body: some View {
         VStack(alignment: .leading, spacing: DesignConstants.Spacing.step4x) {
@@ -58,6 +59,7 @@ struct WhatIsQuicknameView: View {
             .padding(.top, DesignConstants.Spacing.step4x)
         }
         .padding([.leading, .top, .trailing], DesignConstants.Spacing.step10x)
+        .padding(.bottom, horizontalSizeClass == .regular ? DesignConstants.Spacing.step10x : DesignConstants.Spacing.step6x)
     }
 }
 

Convos/Conversation Detail/ConversationShareView.swift

@@ -17,7 +17,7 @@ struct ConversationShareOverlay: View {
     private static let headerHeight: CGFloat = 40.0
     private static let cardPadding: CGFloat = 40.0
     private static let maxQRSize: CGFloat = 220.0
-    private static let shareSheetFraction: CGFloat = 0.45
+    private static let shareSheetFraction: CGFloat = 0.55
 
     private var qrDisplaySize: CGFloat {
         let screenHeight = UIScreen.main.bounds.height
@@ -187,11 +187,11 @@ private struct ShareSheetPresenter: UIViewControllerRepresentable {
                 popover.sourceView = uiViewController.view
                 popover.sourceRect = CGRect(
                     x: uiViewController.view.bounds.midX,
-                    y: uiViewController.view.bounds.midY,
+                    y: uiViewController.view.bounds.maxY,
                     width: 0,
                     height: 0
                 )
-                popover.permittedArrowDirections = []
+                popover.permittedArrowDirections = .up
             }
 
             activityVC.completionWithItemsHandler = { _, _, _, _ in

Convos/Shared Views/AutoShareSheetView.swift

@@ -72,11 +72,11 @@ private struct ActivityViewController: UIViewControllerRepresentable {
                 popover.sourceView = uiViewController.view
                 popover.sourceRect = CGRect(
                     x: uiViewController.view.bounds.midX,
-                    y: uiViewController.view.bounds.midY,
+                    y: uiViewController.view.bounds.maxY,
                     width: 0,
                     height: 0
                 )
-                popover.permittedArrowDirections = []
+                popover.permittedArrowDirections = .up
             }
 
             activityVC.completionWithItemsHandler = { _, _, _, _ in