Method ensureSealedHistoryRotated

src/node/services/historyService.ts:1024–1046

* One-time-per-process check that seals any pre-boundary prefix left in * chat.jsonl. Newly written boundaries rotate eagerly at write time; this * lazily migrates files produced before rotation existed (or by crashes * between boundary write and rotation).

(workspaceId: string)

   * between boundary write and rotation).
   */
  private async ensureSealedHistoryRotated(workspaceId: string): Promise<void> {
    if (this.sealedRotationChecked.has(workspaceId)) {
      return;
    }
    this.sealedRotationChecked.add(workspaceId);

    try {
      // Cheap unlocked probe first so the common no-op case takes no lock.
      const offset = await this.findLastBoundaryByteOffset(this.getChatHistoryPath(workspaceId));
      if (offset === null || offset === 0) {
        return;
      }
      await this.fileLocks.withLock(workspaceId, () =>
        this.rotateSealedHistoryUnlocked(workspaceId)
      );
    } catch (error) {
      // Rotation is an optimization — reads remain correct on unrotated files.
      log.warn("Failed to rotate sealed chat history", {
        workspaceId,
        error: getErrorMessage(error),
      });
    }
  }

  /**
   * Move the sealed prefix of chat.jsonl (everything before the latest durable