feat(respuesta): CC y adjuntos (10MB) con descarga en el hilo

frontend/src/lib/api.ts

@@ -136,14 +136,72 @@ export async function getComments(ticketId: number) {
 export async function addComment(
   ticketId: number,
   content: string,
-  isInternal: boolean = false
+  isInternal: boolean = false,
+  cc?: string,
+  attachmentIds?: number[]
 ) {
   return fetchApi<{ id: number }>(`/api/helpdesk/comments/${ticketId}`, {
     method: "POST",
-    body: JSON.stringify({ content, isInternal }),
+    body: JSON.stringify({ content, isInternal, cc, attachmentIds }),
   });
 }
 
+// ==================== Adjuntos del ticket ====================
+export interface TicketAttachment {
+  id: number;
+  commentId?: number | null;
+  filename: string;
+  contentType: string;
+  size: number;
+  uploadedBy: string;
+  createdAt: string;
+}
+
+export async function uploadTicketAttachments(ticketId: number, files: File[]) {
+  const token =
+    typeof window !== "undefined" ? localStorage.getItem("helpdesk_token") : null;
+  const form = new FormData();
+  files.forEach((f) => form.append("files", f));
+  const res = await fetch(`${API_BASE}/api/helpdesk/ticket/${ticketId}/attachments`, {
+    method: "POST",
+    headers: token ? { Authorization: `Bearer ${token}` } : {},
+    body: form,
+  });
+  if (!res.ok) {
+    const errorData = await res.json().catch(() => ({}));
+    throw new Error(errorData.message || `API Error: ${res.status}`);
+  }
+  return (await res.json()) as { files: { id: number; filename: string; size: number }[] };
+}
+
+export async function getTicketAttachments(ticketId: number) {
+  return fetchApi<TicketAttachment[]>(`/api/helpdesk/ticket/${ticketId}/attachments`);
+}
+
+export async function downloadAttachment(attachment: TicketAttachment) {
+  const token =
+    typeof window !== "undefined" ? localStorage.getItem("helpdesk_token") : null;
+  const res = await fetch(`${API_BASE}/api/helpdesk/attachments/${attachment.id}`, {
+    headers: token ? { Authorization: `Bearer ${token}` } : {},
+  });
+  if (!res.ok) throw new Error(`No se pudo descargar (${res.status})`);
+  const blob = await res.blob();
+  const url = URL.createObjectURL(blob);
+  const a = document.createElement("a");
+  a.href = url;
+  a.download = attachment.filename;
+  document.body.appendChild(a);
+  a.click();
+  a.remove();
+  setTimeout(() => URL.revokeObjectURL(url), 5000);
+}
+
+export function formatFileSize(bytes: number): string {
+  if (bytes < 1024) return `${bytes} B`;
+  if (bytes < 1024 * 1024) return `${(bytes / 1024).toFixed(1)} KB`;
+  return `${(bytes / (1024 * 1024)).toFixed(1)} MB`;
+}
+
 // ==================== Historial de correos del ticket ====================
 // Integración email <-> ticket: enviados desde soporte (mail.log) +
 // respuestas recibidas (helpdesk.email_inbound). Visible para quien