Revert the timeline optimistic and pagination rework (#2596)

* Add npm release track invariant and beta dist-tag procedure

* Revert "Keep older chat history and image previews stable (#2490)"

The timeline optimistic/pagination rework needs more work than main releases can wait for. Reverted together with #2484; both are reapplied on integration/timeline-optimistic-rework.

* Revert "Stop completed turns from appearing stuck (#2484)"

See the #2490 revert. #2490 built on this submission-authority change, so the two revert and reapply as a pair.

packages/app/src/components/rewind/use-rewind-agent-mutation.ts

@@ -7,6 +7,7 @@ import type { RewindMode } from "./use-rewind-capabilities";
 import { useRewindComposerRestore } from "./composer-restore";
 import { useSessionStore } from "@/stores/session-store";
 import { shouldRestoreComposerForRewindMode } from "./rewind-mode";
+import { clearOptimisticUserMessages } from "@/types/stream";
 import { getHostRuntimeStore } from "@/runtime/host-runtime";
 
 interface UseRewindAgentMutationInput {
@@ -35,6 +36,13 @@ export function useRewindAgentMutation(input: UseRewindAgentMutationInput): {
       }
       await input.client.rewindAgent(input.agentId, input.messageId, mode);
       if (mode !== "files") {
+        if (input.serverId) {
+          const session = useSessionStore.getState().sessions[input.serverId];
+          useSessionStore.getState().setAgentStreamState(input.serverId, input.agentId, {
+            tail: clearOptimisticUserMessages(session?.agentStreamTail.get(input.agentId) ?? []),
+            head: clearOptimisticUserMessages(session?.agentStreamHead.get(input.agentId) ?? []),
+          });
+        }
         const cursor = input.serverId
           ? useSessionStore
               .getState()