Q143: earlier messages come from the database, page by page, back to the first one

Review limit (5) reached; the last finding (exhaustion latched) is fixed
by taking it from each latest hasMore.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/shared/desktop-api.ts

@@ -1,4 +1,4 @@
-import type { ThreadHistory } from "./chat-domain";
+import type { SpaceHistoryPage, ThreadHistory } from "./chat-domain";
 import type { RunRequestRecord } from "./provider-runtime-domain";
 import type { ApprovalDrift } from "./approval-pin";
 import type { DesktopResult } from "./result";
@@ -198,6 +198,8 @@ export interface DesktopApi {
   runRequests(input: { orgId: string; runId: string }): Promise<DesktopResult<RunRequestRecord[]>>;
   /** One thread in full, beyond the snapshot's recent window. */
   chatThreadHistory(input: { orgId: string; threadId: string }): Promise<DesktopResult<ThreadHistory>>;
+  /** The page of a conversation before a loaded message, for history older than the snapshot holds. */
+  chatSpaceHistory(input: { orgId: string; spaceId: string; beforeMessageId: string | null } & ({ limit: number } | { fromMessageId: string })): Promise<DesktopResult<SpaceHistoryPage>>;
   revokeConnector(input: RevokeConnectorInput): Promise<DesktopResult<AppSnapshot>>;
   search(input: SearchInput): Promise<DesktopResult<SearchResultRecord[]>>;
   subscribe(callback: (event: RendererEvent) => void): () => void;