feat(frontend): store lastUserEntry + stepMessages; record user input/choice

frontend/src/store/sessionStore.ts

@@ -10,6 +10,8 @@ interface SessionState {
   pendingWidget: WidgetDescriptor | null;
   transcript: Entry[];
   toasts: { level: string; text: string }[];
+  stepMessages: { level: string; text: string }[];
+  lastUserEntry: { kind: "input" | "choice"; text: string } | null;
   lastSystemEvent: StreamEvent | null;
   currentPhase: string | null;
   applyEvent: (e: StreamEvent) => void;
@@ -17,12 +19,15 @@ interface SessionState {
   resetSession: () => void;
   setPhase: (phase: string | null) => void;
   pushToast: (toast: { level: string; text: string }) => void;
+  setLastUserEntry: (e: { kind: "input" | "choice"; text: string }) => void;
 }
 
 const empty = {
   pendingWidget: null,
   transcript: [] as Entry[],
   toasts: [] as { level: string; text: string }[],
+  stepMessages: [] as { level: string; text: string }[],
+  lastUserEntry: null as { kind: "input" | "choice"; text: string } | null,
   lastSystemEvent: null,
   currentPhase: null as string | null,
 };
@@ -45,7 +50,7 @@ export const useSessionStore = create<SessionState>((set) => ({
         else t.push({ role: "assistant", text: e.text });
         return { transcript: t };
       }
-      if (e.type === "info") return { toasts: [...st.toasts, { level: e.level ?? "info", text: e.text }] };
+      if (e.type === "info") return { stepMessages: [...st.stepMessages, { level: e.level ?? "info", text: e.text }] };
       if (e.type === "system_event") return { lastSystemEvent: e };
       return {};
     }),
@@ -53,4 +58,5 @@ export const useSessionStore = create<SessionState>((set) => ({
   resetSession: () => set({ ...empty }),
   setPhase: (phase) => set({ currentPhase: phase }),
   pushToast: (toast) => set((st) => ({ toasts: [...st.toasts, toast] })),
+  setLastUserEntry: (e) => set({ lastUserEntry: e, stepMessages: [] }),
 }));