i18n complete: all 16 components translated (CZ/HE/RU/UA)

- Custom i18n provider with React Context + localStorage
- Hebrew RTL support (dir=rtl on html)
- All pages + components use t() calls
- FullCalendar + dates locale-aware
- Language selector in Settings wired to context

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/tasks/components/GroupSelector.tsx

@@ -2,6 +2,7 @@
 
 import { useRef, useEffect } from "react";
 import { Group } from "@/lib/api";
+import { useTranslation } from "@/lib/i18n";
 
 interface GroupSelectorProps {
   groups: Group[];
@@ -16,6 +17,7 @@ export default function GroupSelector({
 }: GroupSelectorProps) {
   const scrollRef = useRef<HTMLDivElement>(null);
   const activeRef = useRef<HTMLButtonElement>(null);
+  const { t } = useTranslation();
 
   // Scroll active button into view
   useEffect(() => {
@@ -46,7 +48,7 @@ export default function GroupSelector({
             : "bg-gray-100 text-gray-600 dark:bg-gray-800 dark:text-gray-400 hover:bg-gray-200 dark:hover:bg-gray-700 min-h-[44px]"
         }`}
       >
-        Vse
+        {t("tasks.all")}
       </button>
       {groups.map((g) => (
         <button