feat(i18n): add full Hebrew (he) locale translation

Translates all ~400 UI strings to Hebrew across 16 message modules.
Registers the 'he' locale in the i18n system and adds עברית to the
language picker. Built on top of the rtl-support branch so RTL layout
applies immediately when Hebrew is selected.

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

packages/ui/src/components/folder-selection-view.tsx

@@ -45,6 +45,7 @@ const FolderSelectionView: Component<FolderSelectionViewProps> = (props) => {
     { value: "ru", label: "Русский" },
     { value: "ja", label: "日本語" },
     { value: "zh-Hans", label: "简体中文" },
+    { value: "he", label: "עברית" },
   ]
 
   const selectedLanguageOption = () => languageOptions.find((opt) => opt.value === locale()) ?? languageOptions[0]