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/template.go

@@ -0,0 +1,27 @@
+package service
+
+import (
+	"context"
+
+	"github.com/jackc/pgx/v5/pgtype"
+
+	"git.omukk.dev/wrenn/wrenn/pkg/db"
+)
+
+// TemplateService provides template/snapshot operations shared between the
+// REST API and the dashboard.
+type TemplateService struct {
+	DB *db.Queries
+}
+
+// List returns all templates belonging to the given team. If typeFilter is
+// non-empty, only templates of that type ("base" or "snapshot") are returned.
+func (s *TemplateService) List(ctx context.Context, teamID pgtype.UUID, typeFilter string) ([]db.Template, error) {
+	if typeFilter != "" {
+		return s.DB.ListTemplatesByTeamAndType(ctx, db.ListTemplatesByTeamAndTypeParams{
+			TeamID: teamID,
+			Type:   typeFilter,
+		})
+	}
+	return s.DB.ListTemplatesByTeam(ctx, teamID)
+}