feat(redis): Resolve client addresses from the secret projection.

Adds an Addrs method to the Redis authnFormat interface so client addresses can be delivered through the mounted secret rather than only the infrastructure proto. configFromProto now calls pf.Addrs instead of reading cfg.GetAddrs() directly. When the proto carries addresses they are used as-is; otherwise authenticatedFormat reads the secret key named by the projection's addrs field and parses a comma-separated <host>:<port> list, trimming whitespace around each entry. noSecretFormat continues to return only the proto addresses. This supports provisioned endpoints whose address is not known at config time and arrives via the secret alongside the credentials.

Extracts a config() helper for the shared nil-infra / nil-Redis checks used by both AuthConfig and Addrs, plus a resolveSecret helper that resolves an arbitrary projection field through the secret provider.

Bumps fairway to v1.30.0 for the addrs projection field.

Adds table tests for both formats covering proto passthrough, single and comma-separated secret values, whitespace trimming, and the missing provider, missing projection field, and key-not-found error paths.

Issue: gitlab-com/gl-infra/platform/runway/team#931 (closed)