Refactored to maintain a separate cloud version

Moves 12 packages from internal/ to pkg/ (config, id, validate, events, db,
auth, lifecycle, scheduler, channels, audit, service) so they can be imported
by the enterprise repo as a Go module dependency.

Introduces pkg/cpextension (shared Extension interface + ServerContext) and
pkg/cpserver (Run() entrypoint with functional options) so the enterprise
main.go can call cpserver.Run(cpserver.WithExtensions(...)) without duplicating
the 20-step server bootstrap. Adds db/migrations/embed.go for go:embed access
to OSS SQL migrations from the enterprise module.

cmd/control-plane/main.go is reduced to a 10-line wrapper around cpserver.Run.

pkg/service/user.go

@@ -0,0 +1,70 @@
+package service
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"github.com/jackc/pgx/v5/pgtype"
+
+	"git.omukk.dev/wrenn/wrenn/pkg/db"
+)
+
+// UserService provides user management operations.
+type UserService struct {
+	DB *db.Queries
+}
+
+// AdminUserRow is the shape returned by AdminListUsers.
+type AdminUserRow struct {
+	ID          pgtype.UUID
+	Email       string
+	Name        string
+	IsAdmin     bool
+	IsActive    bool
+	CreatedAt   time.Time
+	TeamsJoined int32
+	TeamsOwned  int32
+}
+
+// AdminListUsers returns a paginated list of all non-deleted users with team counts.
+func (s *UserService) AdminListUsers(ctx context.Context, limit, offset int32) ([]AdminUserRow, int32, error) {
+	users, err := s.DB.ListUsersAdmin(ctx, db.ListUsersAdminParams{
+		Limit:  limit,
+		Offset: offset,
+	})
+	if err != nil {
+		return nil, 0, fmt.Errorf("list users: %w", err)
+	}
+
+	total, err := s.DB.CountUsersAdmin(ctx)
+	if err != nil {
+		return nil, 0, fmt.Errorf("count users: %w", err)
+	}
+
+	rows := make([]AdminUserRow, len(users))
+	for i, u := range users {
+		rows[i] = AdminUserRow{
+			ID:          u.ID,
+			Email:       u.Email,
+			Name:        u.Name,
+			IsAdmin:     u.IsAdmin,
+			IsActive:    u.IsActive,
+			CreatedAt:   u.CreatedAt.Time,
+			TeamsJoined: u.TeamsJoined,
+			TeamsOwned:  u.TeamsOwned,
+		}
+	}
+	return rows, total, nil
+}
+
+// SetUserActive enables or disables a user account.
+func (s *UserService) SetUserActive(ctx context.Context, userID pgtype.UUID, active bool) error {
+	if err := s.DB.SetUserActive(ctx, db.SetUserActiveParams{
+		ID:       userID,
+		IsActive: active,
+	}); err != nil {
+		return fmt.Errorf("set user active: %w", err)
+	}
+	return nil
+}