chore: auto-commit (28 archivos)

- app.md
- auth.go
- chat.go
- chat.log
- db.go
- frontend/package.json
- frontend/pnpm-lock.yaml
- frontend/src/App.tsx
- frontend/src/Root.tsx
- frontend/src/api.ts
- ...

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

frontend/src/auth.tsx

@@ -0,0 +1,55 @@
+import { createContext, ReactNode, useCallback, useContext, useEffect, useState } from "react";
+import * as api from "./api";
+import { HTTPError } from "./api";
+import type { User } from "./types";
+
+interface AuthCtx {
+  user: User | null;
+  loading: boolean;
+  login: (username: string, password: string) => Promise<void>;
+  register: (username: string, password: string, displayName: string) => Promise<void>;
+  logout: () => Promise<void>;
+}
+
+const Ctx = createContext<AuthCtx | null>(null);
+
+export function AuthProvider({ children }: { children: ReactNode }) {
+  const [user, setUser] = useState<User | null>(null);
+  const [loading, setLoading] = useState(true);
+
+  useEffect(() => {
+    api
+      .getMe()
+      .then(setUser)
+      .catch((e) => {
+        if (!(e instanceof HTTPError) || e.status !== 401) {
+          console.warn("getMe failed", e);
+        }
+      })
+      .finally(() => setLoading(false));
+  }, []);
+
+  const login = useCallback(async (username: string, password: string) => {
+    const u = await api.login(username, password);
+    setUser(u);
+  }, []);
+
+  const register = useCallback(async (username: string, password: string, displayName: string) => {
+    await api.register(username, password, displayName);
+    const u = await api.login(username, password);
+    setUser(u);
+  }, []);
+
+  const logout = useCallback(async () => {
+    await api.logout();
+    setUser(null);
+  }, []);
+
+  return <Ctx.Provider value={{ user, loading, login, register, logout }}>{children}</Ctx.Provider>;
+}
+
+export function useAuth(): AuthCtx {
+  const v = useContext(Ctx);
+  if (!v) throw new Error("useAuth: missing AuthProvider");
+  return v;
+}