Add field vaidations, general improvements

src/components/DoseSchedule.js

@@ -11,6 +11,7 @@ const DoseSchedule = ({ doses, doseIncrement, onUpdateDoses, t }) => {
           <TimeInput
             value={dose.time}
             onChange={newTime => onUpdateDoses(doses.map((d, i) => i === index ? {...d, time: newTime} : d))}
+            errorMessage={t.timeRequired}
           />
           <div className="w-40">
             <NumericInput
@@ -19,6 +20,7 @@ const DoseSchedule = ({ doses, doseIncrement, onUpdateDoses, t }) => {
               increment={doseIncrement}
               min={0}
               unit={t.mg}
+              errorMessage={t.fieldRequired}
             />
           </div>
           <span className="text-gray-600 text-sm flex-1">{t[dose.label] || dose.label}</span>