Data.Clone() was a full JSON marshal/unmarshal round trip (with a
per-record map dance for unknown fields): 6.3ms and ~13.8k allocs per
call on sandbox hardware, and every admin GET paid it at least twice
(RequireAdmin's user lookup + the handler). Clone is now a reflective
deep copy of the plain data graph — byte-identical output, proven
against the JSON clone on the real seed database by
TestCloneEquivalence — at 0.37ms / 538 allocs. CurrentAdmin resolves
the session user under a read-only store View and no longer clones
at all, so an admin GET takes exactly one snapshot. Sandbox
benchmarks (11 servers / 26 customers / 25 nodes): overview
17.2ms -> 0.38ms, servers 13.3 -> 0.85ms, customers 20.5 -> 1.54ms,
nodes 15.8 -> 3.45ms, jobs 13.0 -> 0.39ms per request.
