ConfigurationBinder appends configured collection items to an existing list, so
the pre-filled [None, Sign, SignAndEncrypt] default made "drop None" a no-op:
every deployment that listed only the secure profiles still advertised an
unsigned/unencrypted None endpoint.
EnabledSecurityProfiles is now null by default; ResolveEnabledSecurityProfiles()
applies the unchanged three-profile default only when nothing is configured.
A set-but-empty list fails startup validation and BuildSecurityPolicies no
longer falls back to a None endpoint on empty input (it throws). Sweep of all
options classes found no other non-empty pre-filled collection default.
Tests: options binding (indexed, JSON, env forms, default, empty, bad name), a
booted-server wire test (no None endpoint, None connection refused with
BadSecurityPolicyRejected, secure connection works; default case is the control).
Claude-Session: https://claude.ai/code/session_01GT67ACmpMR7b9LGRPLijMi
Joseph Doherty