ios: add Agent attachments and shared transcript fade

ios/Packages/Sybil/Sources/Sybil/SybilAgentView.swift

@@ -18,8 +18,14 @@ struct SybilAgentView: View {
     private let bottomID = "agent-bottom"
 
     private var readKey: String {
-        "\(room.snapshot.room.cursor):\(atLatest):\(scrollMetrics.atBottom):\(isScrolling):\(room.isObscured):\(room.isModalPresented):\(scenePhase == .active):\(room.isLoading):\(room.snapshot.revision)"
+        "\(room.snapshot.room.cursor):\(atLatest):\(scrollMetrics.atBottom):\(isScrolling):\(room.isObscured):\(room.isModalPresented):\(room.isAttachmentModalPresented):\(scenePhase == .active):\(room.isLoading):\(room.snapshot.revision)"
     }
+    private var visibleReadingAnchor: AgentReadingAnchor? {
+        rowFrames.filter { $0.value.maxY > topInset && $0.value.minY < scrollMetrics.height }
+            .min { $0.value.minY < $1.value.minY }
+            .map { AgentReadingAnchor(id: $0.key, offset: $0.value.minY) }
+    }
+
     var body: some View {
         let rendered = room.snapshot
         let transcript = AgentTranscript(messages: room.messages, startID: historyStartID, limit: historyLimit)
@@ -32,8 +38,9 @@ struct SybilAgentView: View {
                     VStack(alignment: .leading, spacing: 15) {
                         if allMessages.count > displayed.count {
                             Button("Load earlier messages") {
-                                if let anchor = rowFrames.filter({ $0.value.maxY > 0 }).min(by: { $0.value.minY < $1.value.minY }) {
-                                    restoreAnchor = AgentReadingAnchor(id: anchor.key, offset: anchor.value.minY, expectedCount: min(allMessages.count, displayed.count + 100))
+                                if var anchor = visibleReadingAnchor {
+                                    anchor.expectedCount = min(allMessages.count, displayed.count + 100)
+                                    restoreAnchor = anchor
                                 }
                                 atLatest = false
                                 historyLimit += 100
@@ -52,7 +59,7 @@ struct SybilAgentView: View {
                                         .frame(maxWidth: .infinity)
                                         .padding(.vertical, 6)
                                 }
-                                AgentMessageRow(message: message, retry: { room.retry(message.id) })
+                                AgentMessageRow(message: message, room: room, retry: { room.retry(message.id) })
                                 .background(GeometryReader { geometry in
                                     Color.clear.preference(key: AgentRowFrames.self, value: [message.id: geometry.frame(in: .named("agent-scroll"))])
                                 })
@@ -73,7 +80,10 @@ struct SybilAgentView: View {
                     }
                     .scrollTargetLayout()
                     .padding(.horizontal, 16)
-                    .padding(.vertical, 16)
+                    .padding(.bottom, 16)
+                    // Match normal chat: content clears the header, while the
+                    // viewport extends beneath the shared navigation fade.
+                    .padding(.top, 16 + topInset)
                     .frame(maxWidth: SybilLayout.webContentMaxWidth)
                     .frame(maxWidth: .infinity)
                 }
@@ -90,7 +100,8 @@ struct SybilAgentView: View {
                     AgentScrollMetrics(offset: geometry.contentOffset.y,
                         height: geometry.containerSize.height,
                         contentHeight: geometry.contentSize.height,
-                        bottomInset: geometry.contentInsets.bottom, topInset: geometry.contentInsets.top)
+                        bottomInset: geometry.contentInsets.bottom, topInset: geometry.contentInsets.top,
+                        visibleBottom: geometry.visibleRect.maxY)
                 } action: { previous, next in
                     scrollMetrics = next
                     if isScrolling || next.contentHeight <= next.height { atLatest = next.atBottom }
@@ -100,19 +111,20 @@ struct SybilAgentView: View {
                     }
                 }
                 .onPreferenceChange(AgentRowFrames.self) { frames in
-                    let previousAnchor = rowFrames.filter { $0.value.maxY > 0 && $0.value.minY < scrollMetrics.height }
-                        .min { $0.value.minY < $1.value.minY }
-                        .map { AgentReadingAnchor(id: $0.key, offset: $0.value.minY) }
-                    let anchor = restoreAnchor ?? (!atLatest && !isScrolling ? previousAnchor : nil)
+                    let anchor = restoreAnchor ?? (!atLatest && !isScrolling ? visibleReadingAnchor : nil)
                     if let anchor, let frame = frames[anchor.id], abs(frame.minY - anchor.offset) > 1 {
                         // Restore the exact pixel offset after insertion or text
                         // reflow. Normalize the saved frames to
                         // the requested offset so the next layout cannot undo it.
                         let requested = scrollMetrics.offset + frame.minY - anchor.offset
-                        let target = min(max(requested, -scrollMetrics.topInset), max(-scrollMetrics.topInset, scrollMetrics.contentHeight - scrollMetrics.height + scrollMetrics.bottomInset))
+                        let target = min(max(requested, -scrollMetrics.topInset), scrollMetrics.maximumOffset)
                         let appliedShift = target - scrollMetrics.offset
                         rowFrames = frames.mapValues { $0.offsetBy(dx: 0, dy: -appliedShift) }
-                        if abs(appliedShift) > 1 { scrollPosition.scrollTo(y: target) }
+                        if abs(appliedShift) > 1 {
+                            // Geometry reports the raw offset; ScrollPosition uses
+                            // zero at the top inset, including the safe area.
+                            scrollPosition.scrollTo(y: target + scrollMetrics.topInset)
+                        }
                         restoreAnchor = nil
                     } else {
                         rowFrames = frames
@@ -152,16 +164,15 @@ struct SybilAgentView: View {
             statusBar
             composer
         }
-        .padding(.top, topInset)
         .onAppear { room.isSelected = true }
         .onDisappear { room.isSelected = false }
         .task(id: readKey) {
             // This cursor belongs to the rendered snapshot. New network input cancels
             // the task, and cannot be acknowledged while still entering the layout.
             let cursor = rendered.room.cursor
-            guard atLatest, scrollMetrics.atBottom, !isScrolling, !room.isObscured, !room.isModalPresented, scenePhase == .active, !room.isLoading else { return }
+            guard atLatest, scrollMetrics.atBottom, !isScrolling, !room.isObscured, !room.isModalPresented, !room.isAttachmentModalPresented, scenePhase == .active, !room.isLoading else { return }
             try? await Task.sleep(for: .milliseconds(reduceMotion ? 80 : 360))
-            guard !Task.isCancelled, atLatest, scrollMetrics.atBottom, !isScrolling, !room.isObscured, !room.isModalPresented, scenePhase == .active else { return }
+            guard !Task.isCancelled, atLatest, scrollMetrics.atBottom, !isScrolling, !room.isObscured, !room.isModalPresented, !room.isAttachmentModalPresented, scenePhase == .active else { return }
             room.markRead(renderedCursor: cursor)
         }
     }
@@ -190,20 +201,23 @@ struct SybilAgentView: View {
     }
 
     private var canSendComposer: Bool {
-        !room.composer.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty && room.composer.utf16.count <= 40_000
+        room.attachmentDraft.canSend
     }
 
     private var composer: some View {
-        HStack(alignment: .bottom, spacing: 10) {
-            SybilPromptField(
-                text: $room.composer,
-                focused: $composerFocused,
-                submit: submitComposer
-            )
-            .accessibilityIdentifier("agent-composer")
+        VStack(alignment: .leading, spacing: 8) {
+            AgentAttachmentComposer(room: room)
+            HStack(alignment: .bottom, spacing: 10) {
+                SybilPromptField(
+                    text: $room.composer,
+                    focused: $composerFocused,
+                    submit: submitComposer
+                )
+                .accessibilityIdentifier("agent-composer")
 
-            SybilPromptSendButton(canSend: canSendComposer, submit: submitComposer)
-            .accessibilityIdentifier("agent-send")
+                SybilPromptSendButton(canSend: canSendComposer, submit: submitComposer)
+                .accessibilityIdentifier("agent-send")
+            }
         }
         .padding(.horizontal, 14)
         .padding(.bottom, 12)
@@ -211,8 +225,7 @@ struct SybilAgentView: View {
     }
 
     private func submitComposer() {
-        guard canSendComposer, room.send(room.composer) else { return }
-        room.composer = ""
+        guard canSendComposer, room.sendComposer() else { return }
         atLatest = true
     }
 }
@@ -228,6 +241,7 @@ struct AgentAvatar: View {
 
 private struct AgentMessageRow: View {
     var message: Message
+    var room: SybilAgentRoom
     var retry: () -> Void
     private var own: Bool { message.role == .user }
     private var status: String { message.metadata?.objectValue?["status"]?.stringValue ?? "complete" }
@@ -235,6 +249,9 @@ private struct AgentMessageRow: View {
         HStack(alignment: .bottom, spacing: 8) {
             if !own { AgentAvatar().padding(.bottom, 23) }
             VStack(alignment: own ? .trailing : .leading, spacing: 5) {
+                ForEach(message.agentAttachments) { attachment in
+                    AgentAttachmentCard(attachment: attachment, room: room)
+                }
                 MessageBubble(message: message, isSending: false, streamingAssistantPresentation: nil, isForking: false, onFork: nil, agentStyle: true)
                 HStack(spacing: 6) {
                     Text(own ? "You" : "Sybil")
@@ -289,7 +306,12 @@ private struct AgentScrollMetrics: Equatable {
     var contentHeight: CGFloat = 0
     var bottomInset: CGFloat = 0
     var topInset: CGFloat = 0
-    var atBottom: Bool { height > 0 && contentHeight - offset - height + bottomInset <= 24 }
+    var visibleBottom: CGFloat = 0
+    // visibleRect includes the viewport extended into the safe area, as well as
+    // the alignment inset used when a short transcript is pinned to the bottom.
+    var distanceFromBottom: CGFloat { contentHeight + bottomInset - visibleBottom }
+    var atBottom: Bool { height > 0 && distanceFromBottom <= 24 }
+    var maximumOffset: CGFloat { max(-topInset, offset + distanceFromBottom) }
 }
 private struct AgentReadingAnchor {
     var id: String