fix(ui): toolbar CLI sans overlap + retrait du bouton History — #151 #160 (QA verte)

frontend/src/features/layout/LayoutGrid.tsx

@@ -200,7 +200,6 @@ function NodeView({
           workState={workState}
           refreshWorkState={refreshWorkState}
           refitSignal={refitSignal}
-          onOpenConversation={onOpenConversation}
         />
       );
     case "split":
@@ -247,7 +246,6 @@ interface LeafViewProps {
   workState: ProjectWorkState | null;
   refreshWorkState: () => Promise<void>;
   refitSignal: number;
-  onOpenConversation?: (conversationId: string) => void;
 }
 
 /**
@@ -339,11 +337,13 @@ function goToCell(nodeId: string): void {
  *   status/error      3   (in-cell status strip, launch-error banner, notices)
  *   full-cell veils   4   (write-portal + F3 overlays; mutually exclusive)
  *   cell controls     5   (always on top and clickable)
+ *   turn actions      6   (busy-state actions; Cancel must stay visible)
  */
 const CELL_Z = {
   banner: 3,
   veil: 4,
   controls: 5,
+  turnActions: 6,
 } as const;
 
 function LeafView({
@@ -359,7 +359,6 @@ function LeafView({
   workState,
   refreshWorkState,
   refitSignal,
-  onOpenConversation,
 }: LeafViewProps) {
   // A cell can be closed only when it lives inside a (binary) split: closing it
   // collapses the parent split, keeping the *sibling*. Splits are always binary
@@ -679,9 +678,6 @@ function LeafView({
     ) ?? [];
   const busyByWorkState = agentWork?.busy.state === "busy" || Boolean(activeTicket);
   const delegatedTicket = activeTicket?.source.kind === "agent" ? activeTicket : undefined;
-  const historyConversationId =
-    activeTicket?.conversationId ?? conversationId ?? null;
-
   async function interruptCurrentTurn(): Promise<void> {
     if (!agentId || !input) return;
     try {
@@ -1176,20 +1172,21 @@ function LeafView({
           </button>
         )}
       </div>
-      {agentId && (busyByWorkState || inboxDepth > 0 || completedBackgroundTasks.length > 0 || historyConversationId) && (
+      {agentId && (busyByWorkState || inboxDepth > 0 || completedBackgroundTasks.length > 0) && (
         <div
           role="status"
           aria-live="polite"
           style={{
             position: "absolute",
-            top: 30,
+            top: 24,
             left: 4,
-            zIndex: CELL_Z.banner,
+            zIndex: busyByWorkState ? CELL_Z.turnActions : CELL_Z.banner,
             display: "flex",
             maxWidth: "calc(100% - 8px)",
             alignItems: "center",
             gap: 4,
             overflow: "hidden",
+            pointerEvents: "auto",
           }}
         >
           {busyByWorkState && (
@@ -1289,26 +1286,6 @@ function LeafView({
               Cancel
             </button>
           )}
-          {historyConversationId && onOpenConversation && (
-            <button
-              type="button"
-              aria-label={`open cell conversation ${id}`}
-              title="Open conversation history"
-              onClick={() => onOpenConversation(historyConversationId)}
-              style={{
-                flexShrink: 0,
-                border: "1px solid var(--color-border, #3a3a3a)",
-                borderRadius: 3,
-                background: "var(--color-surface, #1e1e1e)",
-                color: "var(--color-content, #e0e0e0)",
-                cursor: "pointer",
-                fontSize: 11,
-                padding: "1px 6px",
-              }}
-            >
-              History
-            </button>
-          )}
         </div>
       )}
       {/* Option 1 (Terminal + MCP): every cell — plain or agent — renders the