feat: unified navigation hub + categories tab + mobile scroll fix

- Navigation: 4 items (Home, Tracker, Finance, Settings)
- Tracker page: tabs for Habits, Tasks, Stats
- Finance: added Categories tab (CRUD)
- AddTransactionModal: fixed mobile scroll with sticky button
- Home: added finance balance widget
- Legacy routes (/habits, /tasks, /stats) redirect to /tracker

src/pages/Home.jsx

@@ -6,6 +6,7 @@ import { format, startOfWeek, differenceInDays, parseISO, isToday, isTomorrow, i
 import { ru } from 'date-fns/locale'
 import { habitsApi } from '../api/habits'
 import { tasksApi } from '../api/tasks'
+import { financeApi } from '../api/finance'
 import { useAuthStore } from '../store/auth'
 import Navigation from '../components/Navigation'
 import CreateTaskModal from '../components/CreateTaskModal'
@@ -96,6 +97,11 @@ export default function Home() {
     queryFn: tasksApi.today,
   })
 
+
+  const { data: financeSummary } = useQuery({
+    queryKey: ["finance-summary"],
+    queryFn: () => financeApi.getSummary(),
+  })
   useEffect(() => {
     if (habits.length > 0) {
       loadTodayLogs()
@@ -301,6 +307,27 @@ export default function Home() {
         )}
 
         {/* Tasks */}
+
+        {/* Finance Summary */}
+        {financeSummary && (
+          <motion.div initial={{ opacity: 0, y: 20 }} animate={{ opacity: 1, y: 0 }} className="card p-5">
+            <h2 className="font-semibold text-gray-900 dark:text-white mb-3">💰 Баланс</h2>
+            <div className="grid grid-cols-3 gap-3">
+              <div className="text-center">
+                <p className="text-lg font-bold text-green-500">+{(financeSummary.total_income || 0).toLocaleString("ru-RU")} ₽</p>
+                <p className="text-xs text-gray-500">Доходы</p>
+              </div>
+              <div className="text-center">
+                <p className="text-lg font-bold text-red-500">-{(financeSummary.total_expense || 0).toLocaleString("ru-RU")} ₽</p>
+                <p className="text-xs text-gray-500">Расходы</p>
+              </div>
+              <div className="text-center">
+                <p className={"text-lg font-bold " + ((financeSummary.balance || 0) >= 0 ? "text-primary-500" : "text-red-500")}>{(financeSummary.balance || 0).toLocaleString("ru-RU")} ₽</p>
+                <p className="text-xs text-gray-500">Баланс</p>
+              </div>
+            </div>
+          </motion.div>
+        )}
         {(activeTasks.length > 0 || !tasksLoading) && (
           <div>
             <div className="flex items-center justify-between mb-4">