Add Away mode and an agent fork tool

mac/Sources/Byre/Startup.swift

@@ -494,12 +494,56 @@ struct ServerPicker: View {
             .padding(.horizontal, 8)
             .padding(.vertical, 3)
             .help("Add Server")
+            AwayToggle()
         }
         .font(Fonts.font(13))
         .fixedSize()
     }
 }
 
+private struct AwayToggle: View {
+    @ViewState private var hover = false
+    @ViewState private var busy = false
+
+    var body: some View {
+        let stores = Servers.shared.origins.compactMap { Servers.shared.connections[$0]?.store }
+        let away = stores.contains { $0.me?.away == true }
+        if !stores.isEmpty {
+            Button {
+                set(!away, stores)
+            } label: {
+                Text("Away")
+                    .foregroundStyle(away ? Palette.accent : hover ? Palette.text : Palette.muted)
+                    .padding(.horizontal, 8)
+                    .padding(.vertical, 3)
+                    .background(away ? Palette.accentTint : .clear, in: RoundedRectangle(cornerRadius: 6))
+                    .contentShape(Rectangle())
+            }
+            .buttonStyle(.plain)
+            .disabled(busy)
+            .padding(.leading, 8)
+            .help(away
+                ? "You're away: byre answers your agents' questions at once, telling them to pick the most likely answer. Click when you're back."
+                : "Go away: byre answers your agents' questions at once, telling them to pick the most likely answer, on every server")
+            .onHover { hover = $0 }
+        }
+    }
+
+    private func set(_ away: Bool, _ stores: [Store]) {
+        busy = true
+        Task {
+            for store in stores {
+                do {
+                    store.me = try await store.api.client.updateAway(body: .json(.init(away: away))).ok.body.json
+                } catch {
+                    log.error("set away: \(errorText(error), privacy: .public)")
+                }
+            }
+            busy = false
+        }
+    }
+}
+
 private struct ServerChip: View {
     let origin: String
     @ViewState private var hover = false