Fix OCPP 1.6 simulator profile config

[lewbei]

Fixes #150.

This keeps the OCPP 1.6 runtime profile list advertised to the central system, but only passes profiles supported by ocpp-manager into default configuration creation and configuration-manager validation.

Changes:

• build the default OCPP 1.6 config from Core + LocalAuthListManagement only
• keep SupportedFeatureProfiles advertising Core, Reservation, RemoteTrigger, and LocalAuthListManagement
• add default config keys needed by startup validation and reservation support
• treat Core as already configured in the runtime profile loop
• register LocalAuthListManagement validation for local auth instead of re-registering core validation
• remove the empty custom-key update handler registration

Verification:

docker run --rm -v "${PWD}:/src" -w /src golang:1.25 bash -c "apt-get update >/dev/null && apt-get install -y pkg-config libnfc-dev >/dev/null && /usr/local/go/bin/gofmt -w cmd/ocpp_v16_profiles.go cmd/ocpp_v16_profiles_test.go cmd/run.go internal/chargepoint/v16/charge_point.go internal/chargepoint/v16/settings.go internal/chargepoint/v16/profiles_test.go && /usr/local/go/bin/go test ./cmd && /usr/local/go/bin/go test ./internal/pkg/configuration/manager && /usr/local/go/bin/go test ./internal/chargepoint/v16 -run 'TestSetProfilesFromConfig'"

Note: the full ./internal/chargepoint/v16 package currently has unrelated existing nil-pointer failures in older tests that construct partially initialized charge points. The focused startup-profile tests added here pass.