Scaffold full-stack volunteer scheduling application

Go backend with domain-based packages (volunteer, schedule, timeoff,
checkin, notification), SQLite storage, JWT auth, and chi router.
React TypeScript frontend with routing, auth context, and pages for
all core features. Multi-stage Dockerfile and docker-compose included.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

web/src/auth.tsx

@@ -0,0 +1,59 @@
+import React, { createContext, useContext, useState, useEffect, ReactNode } from 'react';
+
+interface AuthContextValue {
+  token: string | null;
+  role: string | null;
+  volunteerID: number | null;
+  login: (token: string) => void;
+  logout: () => void;
+}
+
+const AuthContext = createContext<AuthContextValue | null>(null);
+
+function parseJWT(token: string): { volunteer_id: number; role: string } | null {
+  try {
+    const payload = JSON.parse(atob(token.split('.')[1]));
+    return payload;
+  } catch {
+    return null;
+  }
+}
+
+export function AuthProvider({ children }: { children: ReactNode }) {
+  const [token, setToken] = useState<string | null>(() => localStorage.getItem('token'));
+  const [role, setRole] = useState<string | null>(null);
+  const [volunteerID, setVolunteerID] = useState<number | null>(null);
+
+  useEffect(() => {
+    if (token) {
+      const payload = parseJWT(token);
+      setRole(payload?.role ?? null);
+      setVolunteerID(payload?.volunteer_id ?? null);
+    } else {
+      setRole(null);
+      setVolunteerID(null);
+    }
+  }, [token]);
+
+  function login(t: string) {
+    localStorage.setItem('token', t);
+    setToken(t);
+  }
+
+  function logout() {
+    localStorage.removeItem('token');
+    setToken(null);
+  }
+
+  return (
+    <AuthContext.Provider value={{ token, role, volunteerID, login, logout }}>
+      {children}
+    </AuthContext.Provider>
+  );
+}
+
+export function useAuth() {
+  const ctx = useContext(AuthContext);
+  if (!ctx) throw new Error('useAuth must be used within AuthProvider');
+  return ctx;
+}