Name each database target's archive for its webhook and target (closes #376)

Each database target now has its own archive file,
archive-WEBHOOKNAME-TARGETNAME-TARGETID.db, instead of one
archive-WEBHOOKID.db per webhook. delivery.ArchiveFileName builds the
name.

A change of webhook or target name renames its archive files under the
archive writer's lock, before the new name is saved, and back again if
the save fails. Webhook edits, target edits and target creation run one
at a time, so no two of them interleave. A rename never replaces a
file, and one that fails part way moves back what it moved. Deleting a
target evicts only that target's writer. Archive files are never
deleted, and nothing looks for files under the old name.

Model: opus-5-5

internal/delivery/engine_test.go

@@ -351,23 +351,15 @@ func TestDeliverDatabase_ImmediateSuccess(
 
 	db := testWebhookDB(t)
 
-	// The database target archives for real now, so the engine
-	// needs a webhook DB manager to locate the data directory.
-	e := delivery.NewTestEngineWithDB(
-		nil,
-		database.NewTestWebhookDBManager(t.TempDir()),
-		slog.New(slog.NewTextHandler(
-			os.Stderr,
-			&slog.HandlerOptions{Level: slog.LevelDebug},
-		)),
-		&http.Client{Timeout: 5 * time.Second},
-		1,
-	)
+	// The database target archives for real, so the engine needs
+	// the target in the main database and a data directory.
+	env := setupArchiveTest(t)
+	tgt := env.seedDatabaseTarget(t, "")
 
 	event := seedEvent(t, db, `{"db":"target"}`)
-	d := seedDatabaseTargetDelivery(t, db, event, "")
+	d := seedDatabaseTargetDelivery(t, db, event, tgt)
 
-	e.ExportDeliverDatabase(db, d)
+	env.eng.ExportDeliverDatabase(db, d)
 
 	var updated database.Delivery
 
@@ -1332,32 +1324,27 @@ func TestProcessDelivery_RoutesToCorrectHandler(
 
 	db := testWebhookDB(t)
 
-	// The database target archives for real now, so the engine
-	// needs a webhook DB manager to locate the data directory.
-	e := delivery.NewTestEngineWithDB(
-		nil,
-		database.NewTestWebhookDBManager(t.TempDir()),
-		slog.New(slog.NewTextHandler(
-			os.Stderr,
-			&slog.HandlerOptions{Level: slog.LevelDebug},
-		)),
-		&http.Client{Timeout: 5 * time.Second},
-		1,
-	)
+	// The database target archives for real, so the engine needs
+	// the target in the main database and a data directory.
+	env := setupArchiveTest(t)
+	archive := env.seedDatabaseTarget(t, "")
 
 	tests := []struct {
 		name       string
 		targetType database.TargetType
+		targetID   string
 		wantStatus database.DeliveryStatus
 	}{
 		{
 			"database target",
 			database.TargetTypeDatabase,
+			archive.ID,
 			database.DeliveryStatusDelivered,
 		},
 		{
 			"log target",
 			database.TargetTypeLog,
+			uuid.New().String(),
 			database.DeliveryStatusDelivered,
 		},
 	}
@@ -1367,7 +1354,7 @@ func TestProcessDelivery_RoutesToCorrectHandler(
 			t.Parallel()
 
 			runRoutingSubtest(
-				t, db, e, tt.targetType,
+				t, db, env.eng, tt.targetType, tt.targetID,
 				tt.wantStatus,
 			)
 		})
@@ -1379,6 +1366,7 @@ func runRoutingSubtest(
 	db *gorm.DB,
 	e *delivery.Engine,
 	targetType database.TargetType,
+	targetID string,
 	wantStatus database.DeliveryStatus,
 ) {
 	t.Helper()
@@ -1386,8 +1374,7 @@ func runRoutingSubtest(
 	event := seedEvent(t, db, `{"routing":"test"}`)
 
 	dlv := seedDelivery(
-		t, db, event.ID,
-		uuid.New().String(),
+		t, db, event.ID, targetID,
 		database.DeliveryStatusPending,
 	)