Splitting privileged tests into *_privileged_test.go left their shared helpers in
the untagged files, so in the default (no-tag) build they had no callers and
golangci-lint flagged them as unused.
Moved the privileged-only helpers into the privileged files next to their callers
(generateDummyHandler; createEngine/startSignal/startManagement/getConnectedPeers/
getPeers + kaep/kasp; (*mockDaemon).setJWTToken). Annotated the shared routing-test
fixtures that must stay untagged for cross-platform compilation with //nolint:unused
(systemops_bsd expected* vars, ensureIPv6DefaultRoute on bsd/windows,
loopbackIfaceWindows), matching the existing linux variant.
Tests that need root or mutate host state (nftables/iptables/DNS, TUN/WireGuard
interfaces, routes, eBPF, SSH/service install) are now gated behind a
//go:build privileged tag. The default `go test ./client/...` runs as a non-root
user with no sudo and leaves host networking untouched; mixed files were split so
pure-logic tests stay in the default suite.
A self-hosting ory/dockertest/v4 harness (client/testutil/privileged) runs the
privileged suite inside a --privileged --cap-add=NET_ADMIN container via
`make test-privileged`; a DOCKER_CI=true guard skips the spawn when already inside
the container. Added `make test-unit` for the host-safe run.
