Paging Session Documentation Contradicts the Implementation #4131

The "Paging Sessions" section of the API documentation describes an older implementation, so readers plan around numbers the server does not honour.

Two areas are affected:

• Backwards navigation: the documentation states that the chain of preceding page positions carried by a previous link is limited to the most recent 30 pages. The implementation limits it to 10, so the previous link disappears much earlier than documented.
• Page ID encryption and expiry: the documentation states that keys are rotated every two hours, that a key is valid for at most four hours and that three keys are stored, and that a paging session expires after one hour. The implementation rotates hourly by default and retires a key three rotation periods after it stopped being primary, so a paging link stays usable for at least three hours and is dead after five.

The documentation should state the values the implementation actually uses.

Why: these numbers describe how long a client can keep paging and how long a historic database state — including resources deleted in the meantime — stays reachable through a link. Getting them wrong misleads both integrators and anyone reasoning about data retention.