feat(api): CRUD files/folders + upload multipart réels (scope owner, soft-delete, conteurs d'erreurs)

- repository.Resources (insert/list/get/soft-delete scoping owner_id, UNIQUE(parent_id,name) → NAME_CONFLICT) + Devices.Upsert au register
- service.Resources : DTOs {id,name,size,mimeType,folderId,createdAt,updatedAt}, upload → UPLOAD_DIR/<device>/<id>.<ext> (nettoyage si métadonnée échoue)
- handlers : files list/get/delete/upload + folders racines ; routes consolidées dans handlers.RegisterRoutes
- dbtest package : test DB jetée par repo (open+reset+migrate, skip si PG down) ; tests repository + handlers end-to-end (register→token→CRUD, scoping cross-device, FILE_TOO_LARGE, NAME_CONFLICT)
- docs: /devices persiste le device, layout UPLOAD_DIR par device, codes NAME_CONFLICT/SERVICE_UNAVAILABLE

backend/repository/resources_test.go

@@ -0,0 +1,114 @@
+package repository
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/vaultdrop/backend/dbtest"
+)
+
+const repositoryTestURL = "postgres://vaultdrop:vaultdrop@localhost:5432/vaultdrop_repository_test?sslmode=disable"
+
+func newTestResources(t *testing.T) *Resources {
+	t.Helper()
+	conn := dbtest.OpenTestDatabase(t, repositoryTestURL)
+	return &Resources{DB: conn}
+}
+
+func mustInsertDevice(t *testing.T, repo *Resources, deviceID string) {
+	t.Helper()
+	dev := &Devices{DB: repo.DB}
+	if err := dev.Upsert(deviceID); err != nil {
+		t.Fatalf("upsert device: %v", err)
+	}
+}
+
+func TestCRUDScopedByOwner(t *testing.T) {
+	repo := newTestResources(t)
+	owner := NewID()
+	other := NewID()
+	mustInsertDevice(t, repo, owner)
+	mustInsertDevice(t, repo, other)
+
+	folderID := NewID()
+	if err := repo.InsertFolder(owner, folderID, "Docs", ""); err != nil {
+		t.Fatalf("insert folder: %v", err)
+	}
+
+	mime := "text/plain"
+	ext := "txt"
+	fileID := NewID()
+	if err := repo.InsertFile(owner, fileID, "note.txt", folderID, 42, &mime, &ext); err != nil {
+		t.Fatalf("insert file: %v", err)
+	}
+
+	got, err := repo.GetFile(owner, fileID)
+	if err != nil {
+		t.Fatalf("get file: %v", err)
+	}
+	if got.Name != "note.txt" || got.FolderID != folderID || got.Size != 42 {
+		t.Errorf("file row inattendu: %+v", got)
+	}
+
+	files, total, err := repo.ListFiles(owner, folderID, 10, 0, "created_at", "desc")
+	if err != nil {
+		t.Fatalf("list files: %v", err)
+	}
+	if total != 1 || len(files) != 1 || files[0].ID != fileID {
+		t.Errorf("list folder: total=%d files=%+v", total, files)
+	}
+
+	roots, err := repo.ListRootFolders(owner)
+	if err != nil {
+		t.Fatalf("list roots: %v", err)
+	}
+	if len(roots) != 1 || roots[0].ID != folderID {
+		t.Errorf("roots: %+v", roots)
+	}
+
+	if _, err := repo.GetFile(other, fileID); err != ErrNotFound {
+		t.Errorf("autre device doit voir NOT_FOUND, got %v", err)
+	}
+
+	deleted, err := repo.DeleteFile(owner, fileID)
+	if err != nil || deleted != fileID {
+		t.Fatalf("delete file: %v %v", deleted, err)
+	}
+	if _, err := repo.GetFile(owner, fileID); err != ErrNotFound {
+		t.Errorf("après suppression: %v", err)
+	}
+}
+
+func TestNameConflictAndUnknownFolder(t *testing.T) {
+	repo := newTestResources(t)
+	owner := NewID()
+	mustInsertDevice(t, repo, owner)
+
+	folderID := NewID()
+	if err := repo.InsertFolder(owner, folderID, "Docs", ""); err != nil {
+		t.Fatalf("insert folder: %v", err)
+	}
+
+	ext := "txt"
+	if err := repo.InsertFile(owner, NewID(), "note.txt", folderID, 1, nil, &ext); err != nil {
+		t.Fatalf("insert first file: %v", err)
+	}
+	if err := repo.InsertFile(owner, NewID(), "note.txt", folderID, 1, nil, nil); err != ErrNameConflict {
+		t.Errorf("même nom dans le même dossier doit être NAME_CONFLICT, got %v", err)
+	}
+
+	// Le même nom est autorisé dans un dossier différent (UNIQUE(parent_id, name)).
+	otherFolder := NewID()
+	if err := repo.InsertFolder(owner, otherFolder, "Other", ""); err != nil {
+		t.Fatalf("insert folder 2: %v", err)
+	}
+	if err := repo.InsertFile(owner, NewID(), "note.txt", otherFolder, 1, nil, nil); err != nil {
+		t.Errorf("même nom dans un autre dossier : %v", err)
+	}
+
+	unknown := NewID()
+	err := repo.InsertFile(owner, NewID(), "x.txt", unknown, 1, nil, nil)
+	if !errors.Is(err, ErrNotFound) {
+		t.Errorf("folder inconnu doit être NOT_FOUND, got %v", err)
+	}
+}