feat: impl files endpoints

apps/backend/internal/catalog/file.go

@@ -0,0 +1,13 @@
+package catalog
+
+import "time"
+
+type FileInfo struct {
+	ID        string     `json:"id"`
+	Name      string     `json:"name"`
+	Size      int64      `json:"size"`
+	MimeType  string     `json:"mimeType"`
+	CreatedAt time.Time  `json:"createdAt"`
+	UpdatedAt time.Time  `json:"updatedAt"`
+	DeletedAt *time.Time `json:"deletedAt,omitempty"`
+}