Investigate Live Activity Session Load

Nucleic-Session: 044A9B93-AB31-4B6B-9A27-3631261269B1
Co-authored-by: Nucleic <[email protected]>

NucleicRemote/NucleicRemote/Views/SessionDetailView.swift

@@ -31,27 +31,23 @@ struct SessionDetailView: View {
     }
 
     var body: some View {
+        // The detail's height comes from the enclosing GeometryReader — a value fixed by the parent
+        // (the navigation content area), never by anything inside it. The attention cards (approval /
+        // question) cap themselves to this so their buttons stay on-screen. Sourcing it from a
+        // GeometryReader — rather than measuring the transcript, whose height the cards' own bottom
+        // `safeAreaInset` resizes — makes the measurement categorically independent of the card, so
+        // the card can't feed its height back into the value it's sized from. That feedback was an
+        // unresolved layout cycle that pinned the main thread at 100% CPU during the push transition;
+        // it showed up intermittently because a feedback loop only diverges for some content/card-
+        // height combinations. It bit only the attention path (a card consumes this value; the plain
+        // composer doesn't), which is why a "Working" tap opened fine and an "attention" tap hung.
+        GeometryReader { proxy in
             TranscriptList(events: store.openEvents,
                            scrollToBottomRequest: scrollToBottomRequest,
                            isScrolledToBottom: $isScrolledToBottom)
                 // The chat bar floats over the scrolling content on Liquid Glass instead of sitting
                 // in a boxed strip below it, so the transcript runs the full height of the screen.
                 .safeAreaInset(edge: .bottom) { actionArea }
-            // Measure the whole detail's height — the screen area the action card must fit within —
-            // and hand it to the card so it can cap itself and keep Allow/Deny (or Submit) on-screen.
-            // Measured *after* the safeAreaInset on purpose: this must be the fixed container height,
-            // not the transcript's inset-reduced height. The attention cards (approval / question)
-            // size themselves off `availableHeight` via `.frame(maxHeight:)`, so measuring it from the
-            // inset-reduced region fed the card's own height back into the value it was sized from — a
-            // layout cycle SwiftUI never resolved, pinning the main thread at 100% CPU during the push
-            // transition. It bit only the attention path (a card consumes this value; the plain
-            // composer doesn't), which is why a "Working" tap opened fine and an "attention" tap hung.
-            .background {
-                GeometryReader { proxy in
-                    Color.clear.preference(key: AvailableHeightKey.self, value: proxy.size.height)
-                }
-            }
-            .onPreferenceChange(AvailableHeightKey.self) { availableHeight = $0 }
                 .navigationTitle(summary?.title ?? "Session")
                 .navigationBarTitleDisplayMode(.inline)
                 // With a session open the floating chat bar owns the bottom edge, so the compact
@@ -87,6 +83,14 @@ struct SessionDetailView: View {
                 // disappears) unsubscribes A without tearing down B's just-opened state.
                 .onDisappear { store.closeOpen(sessionID) }
                 .background { interruptShortcut }
+                // Publish the parent-determined height to the cards. `initial: true` seeds it on the
+                // first layout; it refreshes if the container resizes (rotation, keyboard, iPad split
+                // resize). Because `proxy.size.height` never depends on the card, updating this can't
+                // re-drive the measurement — no cycle.
+                .onChange(of: proxy.size.height, initial: true) { _, height in
+                    availableHeight = height
+                }
+        }
     }
 
     /// ⌘. interrupts a running session (the Mac's "stop" convention) — the action is otherwise