```ts

/**
 * Determines the order in which callers are served based on their join time and rank.
 * @param events - An array of log entries with "kind", "tick", "who" (optional), and "rank" (optional).
 * @param step - The aging step size, a positive whole number.
 * @returns An array of names in the order they were served.
 */
export function agedServiceOrder(events: Array<Record<string, unknown>>, step: number): string[] {
    if (step <= 0 || !Number.isInteger(step)) {
        throw new Error("Step must be a positive whole number.");
    }
    if (events.length === 0) {
        throw new Error("Log cannot be empty.");
    }

    const waitingRoom: { name: string, rank: number, joinTick: number }[] = [];
    const served: string[] = [];

    for (const event of events) {
        const kind = event.kind as string;
        const tick = event.tick as number;

        if (kind !== "join" && kind !== "call") {
            throw new Error("Event kind must be either 'join' or 'call'.");
        }
        if (!Number.isInteger(tick) || tick < 0) {
            throw new Error("Tick must be a non-negative whole number.");
        }

        if (kind === "join") {
            const who = event.who as string;
            const rank = event.rank as number;

            if (typeof who !== "string" || who.length === 0) {
                throw new Error("Caller name must be a non-empty string.");
            }
            if (!Number.isInteger(rank) || rank < 0) {
                throw new Error("Rank must be a non-negative whole number.");
            }

            if (waitingRoom.some(entry => entry.name === who)) {
                throw new Error("A caller cannot join the waiting room more than once.");
            }

            waitingRoom.push({ name: who, rank, joinTick: tick });
        } else if (kind === "call") {
            if (waitingRoom.length === 0) {
                throw new Error("Cannot call from an empty waiting room.");
            }

            waitingRoom.sort((a, b) => {
                const standingA = a.rank + Math.floor((tick - a.joinTick) / step);
                const standingB = b.rank + Math.floor((tick - b.joinTick) / step);

                if (standingA !== standingB) {
                    return standingB - standingA;
                }
                if (a.joinTick !== b.joinTick) {
                    return a.joinTick - b.joinTick;
                }
                return a.name.localeCompare(b.name);
            });

            served.push(waitingRoom.shift()!.name);
        }
    }

    return served;
}

```