Fix SSL SAN cert + React hydration #423

- SAN cert covers all 5 PWA domains (tasks,cal,plans,goals,chat)
- i18n hydration: SSR uses cs default, localStorage after mount
- Matches ThemeProvider pattern

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

apps/tasks/lib/i18n.tsx

@@ -57,13 +57,11 @@ export function I18nProvider({ children }: { children: ReactNode }) {
   const [mounted, setMounted] = useState(false);
 
   useEffect(() => {
-    setMounted(true);
-    if (typeof window !== "undefined") {
-      const stored = localStorage.getItem(STORAGE_KEY) as Locale | null;
-      if (stored && MESSAGES[stored]) {
-        setLocaleState(stored);
-      }
+    const stored = localStorage.getItem(STORAGE_KEY) as Locale | null;
+    if (stored && MESSAGES[stored]) {
+      setLocaleState(stored);
     }
+    setMounted(true);
   }, []);
 
   const setLocale = useCallback((newLocale: Locale) => {
@@ -73,29 +71,32 @@ export function I18nProvider({ children }: { children: ReactNode }) {
     }
   }, []);
 
+  // Always use "cs" for translations until mounted to match SSR output
+  const activeLocale = mounted ? locale : "cs";
+
   const t = useCallback(
     (key: string): string => {
-      const value = getNestedValue(MESSAGES[locale], key);
+      const value = getNestedValue(MESSAGES[activeLocale], key);
       if (value !== undefined) return value;
       // Fallback: return last segment of the key (the raw value) instead of "undefined"
       return key.split(".").pop() || key;
     },
-    [locale]
+    [activeLocale]
   );
 
-  const localeInfo = LOCALES.find((l) => l.code === locale) || LOCALES[0];
+  const localeInfo = LOCALES.find((l) => l.code === activeLocale) || LOCALES[0];
   const dir = localeInfo.dir;
   const isRTL = dir === "rtl";
 
-  // Update html attributes when locale changes
+  // Update html attributes when locale changes (only after mount)
   useEffect(() => {
     if (!mounted) return;
     document.documentElement.lang = locale;
-    document.documentElement.dir = dir;
-  }, [locale, dir, mounted]);
+    document.documentElement.dir = LOCALES.find((l) => l.code === locale)?.dir || "ltr";
+  }, [locale, mounted]);
 
   return (
-    <I18nContext.Provider value={{ locale, setLocale, t, dir, isRTL }}>
+    <I18nContext.Provider value={{ locale: activeLocale, setLocale, t, dir, isRTL }}>
       {children}
     </I18nContext.Provider>
   );