feat: frontend alumnos sam-pruebas (RUT+clave, rendir y mis resultados)

frontend/app/lib/session.tsx

@@ -0,0 +1,58 @@
+"use client";
+import { createContext, useContext, useEffect, useState } from "react";
+
+export interface AlumnoUser {
+  idAlumno: string;
+  nombres: string;
+  apPaterno: string;
+  apMaterno?: string;
+  email: string;
+  /** De qué tabla viene: SAM (sige_sam_v3.alumnos) o EMPRESA (sige_sam_empresa.alumnos). */
+  origen: string;
+}
+
+interface SessionCtx {
+  user: AlumnoUser | null;
+  loading: boolean;
+  login: (idAlumno: string, password: string) => Promise<void>;
+  logout: () => Promise<void>;
+}
+
+const Ctx = createContext<SessionCtx | null>(null);
+
+export function SessionProvider({ children }: { children: React.ReactNode }) {
+  const [user, setUser] = useState<AlumnoUser | null>(null);
+  const [loading, setLoading] = useState(true);
+
+  useEffect(() => {
+    fetch("/api/auth/me")
+      .then((r) => (r.ok ? r.json() : null))
+      .then((d) => setUser(d?.user ?? null))
+      .catch(() => setUser(null))
+      .finally(() => setLoading(false));
+  }, []);
+
+  async function login(idAlumno: string, password: string) {
+    const r = await fetch("/api/auth/login", {
+      method: "POST",
+      headers: { "Content-Type": "application/json" },
+      body: JSON.stringify({ idAlumno, password })
+    });
+    const d = await r.json().catch(() => null);
+    if (!r.ok || !d?.success) throw new Error(d?.message || "Credenciales inválidas");
+    setUser(d.user);
+  }
+
+  async function logout() {
+    await fetch("/api/auth/logout", { method: "POST" });
+    setUser(null);
+  }
+
+  return <Ctx.Provider value={{ user, loading, login, logout }}>{children}</Ctx.Provider>;
+}
+
+export function useSession() {
+  const ctx = useContext(Ctx);
+  if (!ctx) throw new Error("useSession fuera de SessionProvider");
+  return ctx;
+}