Adapt frontend to SAM API: RUT auth, new types, helpdesk endpoints

- Login: RUT-based (SAM auth) instead of email
- API client: updated all endpoints to /api/helpdesk/*
- Types: match SAM response format (nombre, apPaterno, perfil)
- Dashboard: uses new DashboardStats with dailyCounts
- Tickets: title instead of subject, requesterName/assigneeName
- KB: categoryName/authorName instead of nested objects
- Removed register page (SAM manages users)

frontend/src/lib/auth.tsx

@@ -5,7 +5,7 @@ import { getMe, login as apiLogin, type User } from "./api";
 
 interface AuthContextType {
   user: User | null;
-  login: (email: string, password: string) => Promise<void>;
+  login: (rut: string, password: string) => Promise<void>;
   logout: () => void;
   isAuthenticated: boolean;
   isLoading: boolean;
@@ -27,22 +27,21 @@ export function AuthProvider({ children }: { children: React.ReactNode }) {
     const token = localStorage.getItem("helpdesk_token");
     if (token) {
       getMe()
-        .then((u) => {
-          setUser(u);
-        })
-        .catch(() => {
-          localStorage.removeItem("helpdesk_token");
-        })
+        .then((u) => setUser(u))
+        .catch(() => localStorage.removeItem("helpdesk_token"))
         .finally(() => setIsLoading(false));
     } else {
       setIsLoading(false);
     }
   }, []);
 
-  const login = useCallback(async (email: string, password: string) => {
-    const { token, user } = await apiLogin(email, password);
-    localStorage.setItem("helpdesk_token", token);
-    setUser(user);
+  const login = useCallback(async (rut: string, password: string) => {
+    const result = await apiLogin(rut, password);
+    if (!result.success || !result.token) {
+      throw new Error(result.message || "Credenciales inválidas");
+    }
+    localStorage.setItem("helpdesk_token", result.token);
+    if (result.user) setUser(result.user);
   }, []);
 
   const logout = useCallback(() => {