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/utils/agent-directory-sync.test.ts

@@ -7,7 +7,6 @@ import { useSessionStore } from "@/stores/session-store";
 import { normalizeAgentSnapshot } from "@/utils/agent-snapshots";
 import { isAgentArchiving, setAgentArchiving } from "@/hooks/use-archive-agent";
 import { queryClient } from "@/data/query-client";
-import { createUserMessage } from "@/types/stream";
 import { applyAgentDirectoryDelta, replaceFetchedAgentDirectory } from "./agent-directory-sync";
 
 function createAgentPayload(
@@ -65,111 +64,6 @@ function permission(id: string): AgentPermissionRequest {
   return { id, provider: "codex", name: id, kind: "tool", title: id };
 }
 
-function beginPendingSubmission(serverId: string, agentId: string): string {
-  const clientMessageId = `client-${agentId}`;
-  useSessionStore.getState().beginAgentMessageSubmission(
-    serverId,
-    agentId,
-    createUserMessage({
-      clientMessageId,
-      text: "Run this",
-      timestamp: new Date("2026-07-27T10:00:00.000Z"),
-    }),
-  );
-  return clientMessageId;
-}
-
-function applyAgentStatus(input: {
-  serverId: string;
-  agentId: string;
-  status: AgentSnapshotPayload["status"];
-  updatedAt: string;
-}): void {
-  const agent = createAgentPayload({
-    id: input.agentId,
-    status: input.status,
-    updatedAt: input.updatedAt,
-  });
-  applyAgentDirectoryDelta({
-    serverId: input.serverId,
-    delta: { kind: "upsert", agent, project: createEntry(agent).project },
-  });
-}
-
-describe("message submission authority", () => {
-  it("does not settle a submission from an unrelated running transition", () => {
-    const serverId = "server-running-is-not-submission-ack";
-    const agentId = "agent-1";
-    const store = useSessionStore.getState();
-    store.initializeSession(serverId, null as unknown as DaemonClient);
-    applyAgentStatus({
-      serverId,
-      agentId,
-      status: "idle",
-      updatedAt: "2026-07-27T10:00:00.000Z",
-    });
-    const clientMessageId = beginPendingSubmission(serverId, agentId);
-
-    applyAgentStatus({
-      serverId,
-      agentId,
-      status: "running",
-      updatedAt: "2026-07-27T10:00:01.000Z",
-    });
-
-    expect(useSessionStore.getState().sessions[serverId]?.messageSubmissions.get(agentId)).toEqual([
-      {
-        clientMessageId,
-        submittedAt: new Date("2026-07-27T10:00:00.000Z"),
-        rpcAccepted: false,
-        providerAcknowledged: false,
-      },
-    ]);
-    store.clearSession(serverId);
-  });
-
-  it("settles provider acknowledgement only when timeline ingestion reports it", () => {
-    const serverId = "server-explicit-provider-ack";
-    const agentId = "agent-1";
-    const store = useSessionStore.getState();
-    store.initializeSession(serverId, null as unknown as DaemonClient);
-    applyAgentStatus({
-      serverId,
-      agentId,
-      status: "idle",
-      updatedAt: "2026-07-27T10:00:00.000Z",
-    });
-    const clientMessageId = beginPendingSubmission(serverId, agentId);
-    store.setAgentStreamState(serverId, agentId, {
-      tail: [
-        createUserMessage({
-          id: "provider-message",
-          messageId: "provider-message",
-          clientMessageId,
-          text: "Run this",
-          timestamp: new Date("2026-07-27T10:00:01.000Z"),
-        }),
-      ],
-      head: [],
-    });
-
-    expect(
-      useSessionStore.getState().sessions[serverId]?.messageSubmissions.get(agentId)?.[0]
-        ?.providerAcknowledged,
-    ).toBe(false);
-
-    store.setAgentStreamState(serverId, agentId, {
-      acknowledgedClientMessageIds: [clientMessageId],
-    });
-
-    expect(
-      useSessionStore.getState().sessions[serverId]?.messageSubmissions.get(agentId)?.[0]
-        ?.providerAcknowledged,
-    ).toBe(true);
-    store.clearSession(serverId);
-  });
-});
-
 describe("replaceFetchedAgentDirectory", () => {
   it("preserves timeline initialization while replacing directory state", () => {
     const serverId = "server-initializing";

packages/app/src/utils/assistant-image-metadata.test.ts

@@ -3,6 +3,7 @@ import {
   clearAssistantImageMetadataCache,
   estimateAssistantMessageHeightFromCache,
   extractAssistantImageSources,
+  getAssistantImageLoadStateFromMetadata,
   getAssistantImageMetadata,
   setAssistantImageMetadata,
 } from "./assistant-image-metadata";
@@ -41,6 +42,23 @@ describe("assistant image metadata", () => {
     });
   });
 
+  it("maps missing metadata to the image loading state", () => {
+    expect(getAssistantImageLoadStateFromMetadata(null)).toEqual({ status: "loading" });
+  });
+
+  it("maps cached metadata to the image ready state", () => {
+    expect(
+      getAssistantImageLoadStateFromMetadata({
+        width: 900,
+        height: 1600,
+        aspectRatio: 9 / 16,
+      }),
+    ).toEqual({
+      status: "ready",
+      aspectRatio: 9 / 16,
+    });
+  });
+
   it("estimates assistant message height from cached image metadata", () => {
     setAssistantImageMetadata(
       {

packages/app/src/utils/assistant-image-metadata.ts

@@ -8,6 +8,11 @@ export interface AssistantImageMetadata {
   aspectRatio: number;
 }
 
+export type AssistantImageLoadState =
+  | { status: "loading" }
+  | { status: "ready"; aspectRatio: number }
+  | { status: "error" };
+
 const assistantImageMetadataCache = new Map<string, AssistantImageMetadata>();
 const assistantImageParseCache = new Map<string, { sources: string[]; hasNonImageText: boolean }>();
 const ASSISTANT_IMAGE_METADATA_CACHE_LIMIT = 500;
@@ -126,6 +131,15 @@ export function getAssistantImageMetadata(input: {
   return null;
 }
 
+export function getAssistantImageLoadStateFromMetadata(
+  metadata: AssistantImageMetadata | null,
+): AssistantImageLoadState {
+  if (!metadata) {
+    return { status: "loading" };
+  }
+  return { status: "ready", aspectRatio: metadata.aspectRatio };
+}
+
 export function setAssistantImageMetadata(
   input: {
     source: string;