Get purchase history

Retrieve audit-style history entries for one purchase.

Use this endpoint to render chronological activity feeds for a purchase.

Behavior:

• Verifies purchase ownership first.
• Returns entries newest-first.
• Includes related order/order-item references and user metadata where available.
• Captures cross-party actions so buyers can understand exactly what changed and when.

Responses:

• Returns 404 for missing or non-owned purchases.
• Returns a normalized timeline payload suitable for rendering directly in activity feeds.