fix: use ObjectID timestamp for createdTime sorting

[Leoyishou]

Problem

When using sortBy: "createdTime" with sortOrder: "desc", the tasks are not sorted correctly by creation time. The oldest tasks appear first instead of the newest.

Root Cause

The current implementation uses the sortOrder field as a proxy for creation time:

case "createdTime": {
    const orderA = a.sortOrder ?? 0;
    const orderB = b.sortOrder ?? 0;
    comparison = orderA - orderB;
    break;
}

However, sortOrder values are extremely large negative numbers (e.g., -8936026338357117000), which is approximately 8.9×10^18. This exceeds JavaScript's safe integer range (Number.MAX_SAFE_INTEGER = 2^53 - 1 ≈ 9×10^15).

When arithmetic operations are performed on these values, precision is lost, resulting in incorrect comparison results.

Solution

Extract the actual Unix timestamp from MongoDB ObjectID. The first 8 hexadecimal characters of an ObjectID represent a Unix timestamp in seconds.

case "createdTime": {
    const getTimestampFromId = (id: string | undefined): number => {
        if (typeof id === 'string' && id.length >= 8) {
            return parseInt(id.substring(0, 8), 16);
        }
        return 0;
    };
    const timeA = getTimestampFromId(a.id);
    const timeB = getTimestampFromId(b.id);
    comparison = timeA - timeB;
    break;
}

Testing

Before fix:

Task 1 (2025-08-31) → Task 2 (2025-09-01) → ... → Task 50 (2025-12-17)

(Oldest first, regardless of sortOrder setting)

After fix:

Task 50 (2025-12-17) → ... → Task 2 (2025-09-01) → Task 1 (2025-08-31)

(Newest first when sortOrder: "desc")

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