fix(btw): discard temporary side threads and save durable forks

design-system/packages/ui/README.md

@@ -625,6 +625,8 @@ Compact tabs use `size="sm"` (30px, 14px icons, 4px icon gap); standard tabs ret
 
 Dialog titles use 24px bold type with their own 29px line box and normal tracking. `DialogHeader` and `DialogFooter` omit separators by default; pass `separator` for a deliberate divider. A direct `DialogBody` sibling of `DialogFooter appearance="floating"` owns the trailing scroll inset automatically. The floating footer provides the 68px centered action area and a masked blur/gradient using the current theme surface; reduced transparency and forced colors use an opaque fallback. Keep scrollable form content inside `DialogBody` instead of adding a second viewport with independent footer spacing.
 
+`ConfirmDialog secondaryActionPlacement="start"` presents an alternative action as a text button at the start of the footer, with cancel and confirm grouped at the end. The groups wrap when space is limited, keeping cancel and confirm together. The default `inline` placement retains the standard action order and outline secondary button.
+
 Extra-large (`xl`) dialogs have an 800px maximum width and continue shrinking within the viewport gutter. Provider editing uses the floating footer; small workspace creation retains its attached footer and existing button/input sizes. The Lab workspace pattern uses local sample paths and callbacks only.
 
 Keep `Dialog` and `Sheet` mounted and set `open={false}` to close them. They retain the last committed children during the exit animation, with interaction disabled, so clearing an owner selection does not collapse the surface. Reopening uses the latest children and cancels the pending exit. Owners that conditionally mount an editor can remove it in `onExitComplete`, which runs once after the surface unmounts.

design-system/packages/ui/src/components/ConfirmDialog/ConfirmDialog.meta.ts

@@ -12,6 +12,7 @@ export const confirmDialogMeta = {
     { defaultValue: "warning", name: "type", type: "info | warning | error | success" },
     { name: "confirmText", type: "ReactNode" },
     { name: "secondaryText", type: "ReactNode" },
+    { defaultValue: "inline", name: "secondaryActionPlacement", type: "inline | start" },
     { name: "cancelText", type: "ReactNode" },
     { name: "preview", type: "ReactNode" },
     { defaultValue: "false", name: "confirmDanger", type: "boolean" },
@@ -42,5 +43,8 @@ export const confirmDialogMeta = {
     "layout.confirmDialog.previewRadius",
     "type.body.md.fontSize",
     "type.code.sm.fontSize",
+    "space.2",
+    "space.3",
+    "space.4",
   ],
 } as const satisfies ComponentMeta;

design-system/packages/ui/src/components/ConfirmDialog/ConfirmDialog.module.css

@@ -3,7 +3,9 @@
   .messageRow,
   .icon,
   .message,
-  .preview {
+  .preview,
+  .splitActions,
+  .actionGroup {
     box-sizing: border-box;
   }
 
@@ -93,6 +95,25 @@
     overflow-wrap: anywhere;
   }
 
+  .splitActions {
+    display: flex;
+    min-inline-size: 0;
+    inline-size: 100%;
+    flex-wrap: wrap;
+    align-items: center;
+    justify-content: space-between;
+    column-gap: var(--openbitfun-space-4);
+    row-gap: var(--openbitfun-space-3);
+  }
+
+  .actionGroup {
+    display: flex;
+    flex: 0 0 auto;
+    align-items: center;
+    gap: var(--openbitfun-space-2);
+    margin-inline-start: auto;
+  }
+
   @media (forced-colors: active) {
     .icon {
       color: CanvasText;

design-system/packages/ui/src/components/ConfirmDialog/ConfirmDialog.tsx

@@ -44,6 +44,8 @@ export interface ConfirmDialogProps {
   open: boolean;
   pendingAction?: "confirm" | "secondary" | null;
   preview?: ReactNode;
+  /** Place an alternative action at the start, separate from cancel and confirm. */
+  secondaryActionPlacement?: "inline" | "start";
   secondaryText?: ReactNode;
   showCancel?: boolean;
   showCloseButton?: boolean;
@@ -75,6 +77,7 @@ export const ConfirmDialog = forwardRef<HTMLDivElement, ConfirmDialogProps>(
     open,
     pendingAction: controlledPendingAction,
     preview,
+    secondaryActionPlacement = "inline",
     secondaryText,
     showCancel = true,
     showCloseButton = false,
@@ -91,6 +94,8 @@ export const ConfirmDialog = forwardRef<HTMLDivElement, ConfirmDialogProps>(
     const resolvedIcon = icon === false ? null : icon ?? defaultIcons[type];
     const hasMessage = message !== undefined && message !== null && message !== "";
     const hasPreview = preview !== undefined && preview !== null && preview !== "";
+    const hasSecondary = secondaryText !== undefined && secondaryText !== null;
+    const secondaryAtStart = hasSecondary && secondaryActionPlacement === "start";
     const resolvedCancelText = cancelText ?? designSystem.messages.confirmCancel;
     const resolvedConfirmText = confirmText ?? designSystem.messages.confirmAction;
 
@@ -125,6 +130,35 @@ export const ConfirmDialog = forwardRef<HTMLDivElement, ConfirmDialogProps>(
       onOpenChange(false, reason);
     }, [busy, onOpenChange]);
 
+    const cancelButton = showCancel ? (
+      <Button disabled={busy} onClick={() => requestClose("cancel-button")} variant="fill">
+        {resolvedCancelText}
+      </Button>
+    ) : null;
+    const secondaryButton = hasSecondary ? (
+      <Button
+        disabled={busy}
+        labelBehavior={secondaryAtStart ? "static" : undefined}
+        loading={pendingAction === "secondary"}
+        onClick={() => void runAction("secondary", onSecondary)}
+        variant={secondaryAtStart ? "text" : "outline"}
+      >
+        {secondaryText}
+      </Button>
+    ) : null;
+    const confirmButton = (
+      <Button
+        disabled={busy}
+        loading={pendingAction === "confirm"}
+        onClick={() => void runAction("confirm", onConfirm)}
+        ref={confirmButtonRef}
+        tone={confirmDanger || type === "error" ? "danger" : "neutral"}
+        variant="primary"
+      >
+        {resolvedConfirmText}
+      </Button>
+    );
+
     return (
       <Dialog
         closeOnEscape={!busy && closeOnEscape}
@@ -186,31 +220,29 @@ export const ConfirmDialog = forwardRef<HTMLDivElement, ConfirmDialogProps>(
           </DialogBody>
         ) : null}
         <DialogFooter>
-          {showCancel ? (
-            <Button disabled={busy} onClick={() => requestClose("cancel-button")} variant="fill">
-              {resolvedCancelText}
-            </Button>
-          ) : null}
-          {secondaryText !== undefined && secondaryText !== null ? (
-            <Button
-              disabled={busy}
-              loading={pendingAction === "secondary"}
-              onClick={() => void runAction("secondary", onSecondary)}
-              variant="outline"
+          {secondaryAtStart ? (
+            <div
+              className={styles.splitActions}
+              data-openbitfun-component="confirm-dialog"
+              data-openbitfun-part="actions"
             >
-              {secondaryText}
-            </Button>
-          ) : null}
-          <Button
-            disabled={busy}
-            loading={pendingAction === "confirm"}
-            onClick={() => void runAction("confirm", onConfirm)}
-            ref={confirmButtonRef}
-            tone={confirmDanger || type === "error" ? "danger" : "neutral"}
-            variant="primary"
-          >
-            {resolvedConfirmText}
-          </Button>
+              {secondaryButton}
+              <div
+                className={styles.actionGroup}
+                data-openbitfun-component="confirm-dialog"
+                data-openbitfun-part="actionGroup"
+              >
+                {cancelButton}
+                {confirmButton}
+              </div>
+            </div>
+          ) : (
+            <>
+              {cancelButton}
+              {secondaryButton}
+              {confirmButton}
+            </>
+          )}
         </DialogFooter>
       </Dialog>
     );

src/crates/assembly/core/src/agentic/coordination/coordinator.rs

@@ -11311,7 +11311,7 @@ Update the persona files and delete BOOTSTRAP.md as soon as bootstrap is complet
                 snapshot.parent_agent_type.clone(),
                 snapshot.build_child_session_config(None),
                 Some(format!("session-{}", snapshot.parent_session_id)),
-                SessionKind::Standard,
+                SessionKind::EphemeralChild,
             )
             .await?;
         self.session_manager
@@ -21722,7 +21722,7 @@ mod tests {
     }
 
     #[tokio::test]
-    async fn btw_session_persists_relationship_and_seeds_forked_listing_baselines() {
+    async fn btw_session_is_ephemeral_and_seeds_forked_listing_baselines() {
         let (coordinator, session_manager) = test_persistent_coordinator();
         // The parent lives in a registered remote workspace; the child must
         // inherit that record's SSH facts rather than transport hints.
@@ -21811,7 +21811,7 @@ mod tests {
 
         assert_eq!(
             child_session.kind,
-            crate::agentic::core::SessionKind::Standard
+            crate::agentic::core::SessionKind::EphemeralChild
         );
         assert_eq!(
             child_session.last_user_dialog_agent_type.as_deref(),
@@ -21871,26 +21871,27 @@ mod tests {
         let metadata = session_manager
             .load_session_metadata(&session_storage_path, &child_session.session_id)
             .await
-            .expect("BTW metadata should load")
-            .expect("BTW metadata should exist");
-        let relationship = metadata
-            .relationship
-            .expect("BTW relationship should persist");
-        assert_eq!(relationship.kind, Some(SessionRelationshipKind::Btw));
-        assert_eq!(
-            relationship.parent_session_id.as_deref(),
-            Some(parent_session.session_id.as_str())
-        );
-        assert_eq!(
-            relationship.parent_request_id.as_deref(),
-            Some("btw-request")
-        );
-        assert_eq!(
-            relationship.parent_dialog_turn_id.as_deref(),
-            Some("parent-turn")
-        );
-        assert_eq!(relationship.parent_turn_index, Some(2));
-        assert_eq!(metadata.memory_mode, SessionMemoryMode::Disabled);
+            .expect("BTW metadata lookup should succeed");
+        assert!(metadata.is_none(), "temporary BTW must not write history");
+        assert!(!session_manager.should_persist_session_id(&child_session.session_id));
+
+        let reused = coordinator
+            .ensure_btw_session(
+                &parent_session.session_id,
+                &child_session.session_id,
+                None,
+                "btw-follow-up",
+                Some("parent-turn"),
+                Some(2),
+            )
+            .await
+            .expect("temporary BTW should accept follow-up questions");
+        assert_eq!(reused.kind, SessionKind::EphemeralChild);
+        assert!(session_manager
+            .load_session_metadata(&session_storage_path, &child_session.session_id)
+            .await
+            .expect("BTW metadata lookup after reuse should succeed")
+            .is_none());
     }
 
     #[test]

src/crates/assembly/core/src/agentic/persistence/manager.rs

@@ -1124,7 +1124,7 @@ impl PersistenceManager {
         }
     }
 
-    async fn build_session_metadata(
+    pub(super) async fn build_session_metadata(
         &self,
         workspace_path: &Path,
         session: &Session,