feat(fleet): add service type enum and infra scope

Replace the free-form service_type string with a ServiceType enum (ccms,
ccmc, ccb, cces, ccsa, ccnc, ccem). The short code is the canonical value
stored in the DB, the config-tree directory name and a NATS discovery
subject token; Description() gives the human-readable name.

Add a second scope alongside per-node agents: ScopeInfra covers
cluster-independent monitoring infrastructure services, which are
identified by (hostname, service_type) and carry an empty cluster.
InfraRegistry is the ScopeInfra sibling of Registry and shares the same
table, state machine and config-revision handshake. It deliberately
exposes no StartSweep: MarkStale ages rows by last_heartbeat regardless
of scope, so a single sweep goroutine per process covers both scopes.

On the repository side ServiceDB gains a Scope column and the two
queries the discovery publisher and infra enumeration need, ListActive()
and ListByScope(). ResetConnection() now also resets the fleet
repository singleton so tests get a fresh handle.

Migration 13 is edited in place rather than superseded by a new
migration: the service table is unreleased, so no existing deployment
has it yet.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

internal/fleet/services_test.go

@@ -0,0 +1,127 @@
+// Copyright (C) NHR@FAU, University Erlangen-Nuremberg.
+// All rights reserved. This file is part of cc-backend.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package fleet
+
+import (
+	"errors"
+	"path/filepath"
+	"testing"
+	"time"
+
+	"github.com/ClusterCockpit/cc-backend/internal/repository"
+	cclog "github.com/ClusterCockpit/cc-lib/v2/ccLogger"
+	_ "github.com/mattn/go-sqlite3"
+)
+
+// setupDB migrates a fresh temp database to the current schema and wires the
+// repository singletons to it, isolated per test.
+func setupDB(t *testing.T) {
+	t.Helper()
+	cclog.Init("warn", true)
+
+	dbfile := filepath.Join(t.TempDir(), "fleet.db")
+	if err := repository.ResetConnection(); err != nil {
+		t.Fatal(err)
+	}
+	if err := repository.MigrateDB(dbfile); err != nil {
+		t.Fatal(err)
+	}
+	repository.Connect(dbfile)
+	t.Cleanup(func() { repository.ResetConnection() })
+}
+
+func TestInfraRegistry(t *testing.T) {
+	setupDB(t)
+	reg := NewInfraRegistry()
+
+	t.Run("register requires hostname and a valid service_type", func(t *testing.T) {
+		if _, err := reg.Register(InfraRegistrationRequest{ServiceType: ServiceTypeMetricStore}); err == nil {
+			t.Fatal("expected error for missing hostname")
+		}
+		if _, err := reg.Register(InfraRegistrationRequest{Hostname: "ms01"}); err == nil {
+			t.Fatal("expected error for missing service_type")
+		}
+		if _, err := reg.Register(InfraRegistrationRequest{Hostname: "ms01", ServiceType: "bogus"}); err == nil {
+			t.Fatal("expected error for unknown service_type")
+		}
+	})
+
+	var instanceID string
+	t.Run("register issues identity with revision 0", func(t *testing.T) {
+		r, err := reg.Register(InfraRegistrationRequest{
+			Hostname: "ms01", ServiceType: ServiceTypeMetricStore,
+			MetaData: map[string]string{"version": "1.2.3"},
+		})
+		if err != nil {
+			t.Fatal(err)
+		}
+		if r.InstanceID == "" || r.ConfigRevision != 0 {
+			t.Fatalf("unexpected registration: %+v", r)
+		}
+		instanceID = r.InstanceID
+	})
+
+	t.Run("get returns infra scope and empty cluster", func(t *testing.T) {
+		svc, err := reg.Get(instanceID)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if svc.Cluster != "" || svc.ServiceType != ServiceTypeMetricStore || svc.State != "pending" {
+			t.Fatalf("unexpected service: %+v", svc)
+		}
+		if svc.MetaData["version"] != "1.2.3" {
+			t.Fatalf("metadata not round-tripped: %+v", svc.MetaData)
+		}
+	})
+
+	t.Run("heartbeat activates known, rejects unknown", func(t *testing.T) {
+		if err := reg.Heartbeat(instanceID, time.Unix(5000, 0)); err != nil {
+			t.Fatal(err)
+		}
+		svc, _ := reg.Get(instanceID)
+		if svc.State != "active" || svc.LastHeartbeat == nil {
+			t.Fatalf("heartbeat did not activate: %+v", svc)
+		}
+		if err := reg.Heartbeat("unknown", time.Unix(5000, 0)); !errors.Is(err, ErrUnknownInstance) {
+			t.Fatalf("want ErrUnknownInstance, got %v", err)
+		}
+	})
+
+	t.Run("list returns only infra services", func(t *testing.T) {
+		// A cluster-scope agent must not appear in the infra listing.
+		cReg := NewRegistry(time.Hour)
+		if _, err := cReg.Register(RegistrationRequest{
+			Cluster: "fritz", Hostname: "node01", ServiceType: ServiceTypeCollector,
+		}); err != nil {
+			t.Fatal(err)
+		}
+
+		list, err := reg.List()
+		if err != nil {
+			t.Fatal(err)
+		}
+		if len(list) != 1 || list[0].ServiceType != ServiceTypeMetricStore {
+			t.Fatalf("unexpected infra list: %+v", list)
+		}
+	})
+
+	t.Run("ack config records revision, deregister is terminal", func(t *testing.T) {
+		if err := reg.AckConfig(instanceID, 99); err != nil {
+			t.Fatal(err)
+		}
+		svc, _ := reg.Get(instanceID)
+		if svc.ConfigRevision != 99 {
+			t.Fatalf("want revision 99, got %d", svc.ConfigRevision)
+		}
+
+		if err := reg.Deregister(instanceID); err != nil {
+			t.Fatal(err)
+		}
+		if err := reg.Heartbeat(instanceID, time.Unix(6000, 0)); !errors.Is(err, ErrUnknownInstance) {
+			t.Fatalf("heartbeat after deregister should fail: %v", err)
+		}
+	})
+}