fix(chat): stabilise le mode CLI custom contre le refetch stale agents/profiles (#149)

Le fallback custom→TUI se redéclenchait après le premier chargement dès que
refreshProfiles() renvoyait un instant un profil pinné sans structuredAdapter
(refetch en vol), coupant la CLI custom ~0.5s après son ouverture. Introduit
un binding "trusted" (agent+profil validés) qui reste valide tant qu'aucun
changement légitime de profil n'est observé via agentProfileChanged, et ne
retombe en TUI que sur perte réelle du CLI custom.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

frontend/src/features/layout/LayoutGrid.tsx

@@ -280,6 +280,30 @@ interface PendingModeSwitch {
   target: AgentCellMode;
 }
 
+interface TrustedCustomCliBinding {
+  agent: Agent;
+  profile: AgentProfile;
+}
+
+export function shouldFallbackCustomCliMode(input: {
+  agentsLoaded: boolean;
+  profilesLoaded: boolean;
+  cellMode: AgentCellMode;
+  hasPinnedAgent: boolean;
+  hasPinnedProfile: boolean;
+  customCliAvailable: boolean;
+  effectiveCustomCliAvailable: boolean;
+  hasTrustedCustomCli: boolean;
+  hasLegitProfileChange: boolean;
+}): boolean {
+  if (!input.agentsLoaded || !input.profilesLoaded) return false;
+  if (input.cellMode !== "custom") return false;
+  if (!input.hasPinnedAgent || !input.hasPinnedProfile) return false;
+  if (!input.customCliAvailable && input.hasLegitProfileChange) return true;
+  if (input.effectiveCustomCliAvailable) return false;
+  return !input.hasTrustedCustomCli;
+}
+
 /**
  * Focuses the layout leaf with the given node id: scrolls it into view and
  * flashes a brief outline so the user sees where the agent already lives. Works
@@ -443,6 +467,14 @@ function LeafView({
   );
   const [pendingModeSwitch, setPendingModeSwitch] =
     useState<PendingModeSwitch | null>(null);
+  const [trustedCustomCli, setTrustedCustomCli] =
+    useState<TrustedCustomCliBinding | null>(null);
+  const legitProfileChangeRef = useRef<{
+    agentId: string;
+    profileId: string;
+    seq: number;
+  } | null>(null);
+  const [legitProfileChangeSeq, setLegitProfileChangeSeq] = useState(0);
 
   // Load the agents currently running (and where), so the dropdown can disable an
   // agent already live in another cell — it cannot run in two cells at once. The
@@ -517,6 +549,40 @@ function LeafView({
       agentGateway?.cancelAgentChat &&
       agentGateway?.closeAgentChat,
   );
+  const trustedCustomCliAvailable = Boolean(
+    cellMode === "custom" &&
+      agentId &&
+      trustedCustomCli?.agent.id === agentId &&
+      trustedCustomCli.profile.structuredAdapter &&
+      agentGateway?.launchAgentChat &&
+      agentGateway?.reattachAgentChat &&
+      agentGateway?.sendAgentChat &&
+      agentGateway?.cancelAgentChat &&
+      agentGateway?.closeAgentChat,
+  );
+  const effectiveCustomCliAvailable =
+    customCliAvailable || trustedCustomCliAvailable;
+  const customCliAgent =
+    customCliAvailable && pinnedAgent ? pinnedAgent : trustedCustomCli?.agent;
+  const customCliProfile =
+    customCliAvailable && pinnedProfile ? pinnedProfile : trustedCustomCli?.profile;
+  useEffect(() => {
+    if (cellMode !== "custom") {
+      setTrustedCustomCli(null);
+      return;
+    }
+    if (!customCliAvailable || !pinnedAgent || !pinnedProfile) return;
+    setTrustedCustomCli((prev) => {
+      if (
+        prev?.agent.id === pinnedAgent.id &&
+        prev.profile.id === pinnedProfile.id &&
+        prev.profile.structuredAdapter === pinnedProfile.structuredAdapter
+      ) {
+        return prev;
+      }
+      return { agent: pinnedAgent, profile: pinnedProfile };
+    });
+  }, [cellMode, customCliAvailable, pinnedAgent, pinnedProfile]);
   useEffect(() => {
     if (!agentId) return;
     refreshAgents();
@@ -532,6 +598,13 @@ function LeafView({
     void system
       .onDomainEvent((event) => {
         if (event.type !== "agentProfileChanged" || event.agentId !== agentId) return;
+        const seq = legitProfileChangeRef.current?.seq ?? 0;
+        legitProfileChangeRef.current = {
+          agentId: event.agentId,
+          profileId: event.profileId,
+          seq: seq + 1,
+        };
+        setLegitProfileChangeSeq(seq + 1);
         refreshAgents();
         refreshProfiles();
       })
@@ -545,17 +618,39 @@ function LeafView({
     };
   }, [agentId, refreshAgents, refreshProfiles, system]);
   useEffect(() => {
-    if (!agentsLoaded || !profilesLoaded) return;
-    if (cellMode !== "custom") return;
-    if (pinnedAgent && pinnedProfile && !customCliAvailable) setCellMode("tui");
+    const legitChange = legitProfileChangeRef.current;
+    const hasLegitDowngrade = Boolean(
+      pinnedAgent &&
+        legitChange?.agentId === pinnedAgent.id &&
+        legitChange.profileId === pinnedAgent.profileId,
+    );
+    if (
+      shouldFallbackCustomCliMode({
+        agentsLoaded,
+        profilesLoaded,
+        cellMode,
+        hasPinnedAgent: Boolean(pinnedAgent),
+        hasPinnedProfile: Boolean(pinnedProfile),
+        customCliAvailable,
+        effectiveCustomCliAvailable,
+        hasTrustedCustomCli: Boolean(trustedCustomCli),
+        hasLegitProfileChange: hasLegitDowngrade,
+      })
+    ) {
+      setTrustedCustomCli(null);
+      setCellMode("tui");
+    }
   }, [
     agentsLoaded,
     cellMode,
     customCliAvailable,
+    effectiveCustomCliAvailable,
+    legitProfileChangeSeq,
     pinnedAgent,
     pinnedProfile,
     profilesLoaded,
     setCellMode,
+    trustedCustomCli,
   ]);
   const modelServerStatus = statusForAgent(pinnedAgent);
   const modelServerOverlay = modelServerOverlayText(modelServerStatus);
@@ -593,7 +688,7 @@ function LeafView({
   }
 
   function requestMode(target: AgentCellMode): void {
-    if (!customCliAvailable || target === cellMode) return;
+    if (!effectiveCustomCliAvailable || target === cellMode) return;
     if (session) setPendingModeSwitch({ target });
     else setCellMode(target);
   }
@@ -953,7 +1048,7 @@ function LeafView({
           })}
         </select>
 
-        {customCliAvailable && (
+        {effectiveCustomCliAvailable && (
           <div
             role="group"
             aria-label={`mode CLI agent ${id}`}
@@ -1193,13 +1288,13 @@ function LeafView({
           minWidth: 0,
         }}
       >
-        {agentId && cellMode === "custom" && customCliAvailable && pinnedAgent && pinnedProfile ? (
+        {agentId && cellMode === "custom" && effectiveCustomCliAvailable && customCliAgent && customCliProfile ? (
           <CustomAgentChatView
             key={`${id}-${agentId}-custom`}
             projectId={projectId}
             agentId={agentId}
-            agentName={pinnedAgent.name}
-            profile={pinnedProfile}
+            agentName={customCliAgent.name}
+            profile={customCliProfile}
             cwd={cwd}
             nodeId={id}
             sessionId={session}