Add admin users, BYOC teams, hosts schema, and Redis for host registration

Introduce three migrations: admin permissions (is_admin + permissions table),
BYOC team tracking, and multi-host support (hosts, host_tokens, host_tags).
Add Redis to dev infra and wire up client in control plane for ephemeral
host registration tokens. Add go-redis dependency.

db/queries/teams.sql

@@ -15,3 +15,9 @@ SELECT t.* FROM teams t
 JOIN users_teams ut ON ut.team_id = t.id
 WHERE ut.user_id = $1 AND ut.is_default = TRUE
 LIMIT 1;
+
+-- name: SetTeamBYOC :exec
+UPDATE teams SET is_byoc = $2 WHERE id = $1;
+
+-- name: GetBYOCTeams :many
+SELECT * FROM teams WHERE is_byoc = TRUE ORDER BY created_at;