fix(ui): stream phase progress without gates

frontend/src/store/sessionStore.test.ts

@@ -184,6 +184,19 @@ test("ui_request without a phase keeps the existing currentPhase", () => {
   expect(useSessionStore.getState().currentPhase).toBe("F2");
 });
 
+test("phase_started advances progress even when the phase has no human gate", () => {
+  const store = useSessionStore.getState();
+  store.setPhase("F1");
+
+  store.applyEvent({
+    type: "system_event",
+    event: "phase_started",
+    phase: "F2_memory",
+  });
+
+  expect(useSessionStore.getState().currentPhase).toBe("F2");
+});
+
 test("agentActive lifecycle: off by default, on with activity, off on agent_end", () => {
   const st = useSessionStore.getState();
   expect(useSessionStore.getState().agentActive).toBe(false);

frontend/src/store/sessionStore.ts

@@ -176,14 +176,26 @@ export const useSessionStore = create<SessionState>((set) => ({
           : { stepMessages, activityLog };
       }
       if (e.type === "system_event") {
+        const currentPhase = e.event === "phase_started"
+          ? phaseOf(e.phase, st.currentPhase)
+          : st.currentPhase;
         const activityLog = [
           ...st.activityLog,
           {
             kind: "lifecycle" as const,
-            phase: st.currentPhase,
+            phase: currentPhase,
             text: lifecycleText(e.event),
           },
         ];
+        if (e.event === "phase_started") {
+          return {
+            lastSystemEvent: e,
+            activityLog,
+            currentPhase,
+            phaseError: null,
+            agentActive: true,
+          };
+        }
         return e.event === "agent_end"
           ? { lastSystemEvent: e, activityLog, agentActive: false }
           : { lastSystemEvent: e, activityLog };