test(cache): cover delayed restore timestamp boundaries

Exercise accepted receipt-time quotas, measured zero, account-key preservation,
missing cached providers, raw failed snapshots, and the original retention
deadline. Keep the author's production fix unchanged.

Supplemental Node execution of these exact QML test function bodies against
the author's implementation passes all five data cases. Four fail against
the original module, while the raw-failure control passes in both versions.
Native Qt/check/smoke results must be verified on this updated branch.
ebe13f6800Simone committed on 9/11/2026, 2:23:31 AMparent35a064c

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