fix(review round 1): daemon PAT-header auth, job pruning, session-split batches, streaming tars, seed cleanup, ping/pong, byte caps, branch switch, slug --, ctx cancel, Init:true, pagination, latest/before events; web newest-window history + load-older, offline busy gate, staleness guards, memo store, auth probe, scroll key, focus-visible, draft restore, poll dedup; 106+181 tests, coverage 96.2%/95.1%+

web/src/ChatView.tsx

@@ -15,6 +15,7 @@ import ChatStream from "./ChatStream";
 import TaskPanel from "./TaskPanel";
 
 const HISTORY_LIMIT: number = 1000;
+const LATEST_QUERY: string = "latest=1";
 const TEXTAREA_MAX_H: number = 200;
 const SEND_KEY: string = "Enter";
 
@@ -32,10 +33,15 @@ export default function ChatView({ store, pushToast }: Props) {
 	const [draft, setDraft] = useState<string>("");
 	const [sending, setSending] = useState<boolean>(false);
 	const [tasksOpen, setTasksOpen] = useState<boolean>(false);
+	const [hasOlder, setHasOlder] = useState<boolean>(false);
+	const [loadingOlder, setLoadingOlder] = useState<boolean>(false);
 
 	const lastSeqRef = useRef<number>(0);
 	const loadedRef = useRef<boolean>(false);
 	const taRef = useRef<HTMLTextAreaElement | null>(null);
+	// guards async fetches against session switches (S1)
+	const sessionIdRef = useRef<string>(sessionId);
+	sessionIdRef.current = sessionId;
 
 	const session = store.sessions.find((s) => s.id === sessionId);
 
@@ -62,21 +68,23 @@ export default function ChatView({ store, pushToast }: Props) {
 		});
 	}, []);
 
-	// history load on mount / session switch
+	// history load on mount / session switch: newest page, ascending (B1)
 	useEffect(() => {
 		if (sessionId.length === 0) return;
 		loadedRef.current = false;
 		setLoadError("");
 		setEvents([]);
+		setHasOlder(false);
 		lastSeqRef.current = 0;
 		let alive = true;
 		void (async () => {
 			try {
 				const evts = await fetchJson<EventFrame[]>(
-					`${Route.SessionEvents(sessionId)}?after=0&limit=${HISTORY_LIMIT}`,
+					`${Route.SessionEvents(sessionId)}?${LATEST_QUERY}&limit=${HISTORY_LIMIT}`,
 				);
 				if (!alive) return;
 				applyEvents(evts);
+				setHasOlder(evts.length >= HISTORY_LIMIT);
 			} catch (err) {
 				if (alive) setLoadError(errMessage(err));
 			} finally {
@@ -94,20 +102,52 @@ export default function ChatView({ store, pushToast }: Props) {
 		return store.subscribe(sessionId, applyEvents);
 	}, [sessionId, store.state, store, applyEvents]);
 
-	// missed events after reconnect (persisted only)
+	// missed events after reconnect (persisted only); a response for a
+	// previous session must not merge here nor touch the cursor (S1)
 	useEffect(() => {
 		if (store.state !== "open" || !loadedRef.current) return;
+		const id: string = sessionId;
 		const after: number = lastSeqRef.current;
 		void fetchJson<EventFrame[]>(
-			`${Route.SessionEvents(sessionId)}?after=${after}&limit=${HISTORY_LIMIT}`,
+			`${Route.SessionEvents(id)}?after=${after}&limit=${HISTORY_LIMIT}`,
 		)
-			.then(applyEvents)
+			.then((evts) => {
+				if (sessionIdRef.current === id) applyEvents(evts);
+			})
 			.catch(() => undefined);
 	}, [store.state, sessionId, applyEvents]);
 
 	const chat = useMemo(() => deriveChat(events), [events]);
 	const tasks = useMemo(() => deriveTasks(events), [events]);
 
+	// a closed/crashed container can never emit agent_settled: an offline
+	// session must never look busy (B2)
+	const busy: boolean = chat.busy && session?.online !== false;
+
+	const minSeq: number = useMemo(
+		() => (events.length === 0 ? 0 : Math.min(...events.map((e) => e.seq))),
+		[events],
+	);
+
+	// previous page (seq < oldest loaded), ascending (B1)
+	const loadOlder = useCallback(async (): Promise<void> => {
+		// the button only renders while a full page is loaded, so minSeq > 0
+		if (sessionIdRef.current !== sessionId || loadingOlder) return;
+		setLoadingOlder(true);
+		try {
+			const evts = await fetchJson<EventFrame[]>(
+				`${Route.SessionEvents(sessionId)}?before=${minSeq}&limit=${HISTORY_LIMIT}`,
+			);
+			if (sessionIdRef.current !== sessionId) return;
+			applyEvents(evts);
+			setHasOlder(evts.length >= HISTORY_LIMIT);
+		} catch (err) {
+			pushToast(errMessage(err));
+		} finally {
+			setLoadingOlder(false);
+		}
+	}, [sessionId, minSeq, loadingOlder, applyEvents, pushToast]);
+
 	const autosize = useCallback((): void => {
 		const el = taRef.current;
 		if (el === null) return;
@@ -128,6 +168,8 @@ export default function ChatView({ store, pushToast }: Props) {
 				body: JSON.stringify({ message: text }),
 			});
 		} catch (err) {
+			// the message never reached the session: put it back (S6)
+			setDraft(text);
 			if (err instanceof ApiError && err.status === 409)
 				pushToast("session offline");
 			else pushToast(errMessage(err));
@@ -215,9 +257,13 @@ export default function ChatView({ store, pushToast }: Props) {
 					</div>
 				) : (
 					<ChatStream
+						key={sessionId}
 						messages={chat.messages}
 						tools={chat.tools}
-						busy={chat.busy}
+						busy={busy}
+						hasOlder={hasOlder}
+						loadingOlder={loadingOlder}
+						onLoadOlder={() => void loadOlder()}
 					/>
 				)}
 				<div className="composer">
@@ -231,7 +277,7 @@ export default function ChatView({ store, pushToast }: Props) {
 							onChange={(e) => setDraft(e.target.value)}
 							onKeyDown={onKeyDown}
 						/>
-						{chat.busy ? (
+						{busy ? (
 							<button
 								type="button"
 								className="abort-btn"