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>

internal/respond/respond.go

@@ -0,0 +1,16 @@
+package respond
+
+import (
+	"encoding/json"
+	"net/http"
+)
+
+func JSON(w http.ResponseWriter, status int, v any) {
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(status)
+	json.NewEncoder(w).Encode(v)
+}
+
+func Error(w http.ResponseWriter, status int, msg string) {
+	JSON(w, status, map[string]string{"error": msg})
+}