fix: i18n system overhaul and sidebar UI bugs

- Fix LanguageProvider: add RTL support (ar/fa), translation caching,
  prevent blank flash during load, browser language detection
- Fix detect-user-language: extend whitelist from 5 to all 15 languages
- Remove hardcoded initialLanguage="fr" from auth layout
- Complete fr.json translation (all sections translated from English)
- Add missing admin.ai keys to all 13 non-English locales
- Translate ai.autoLabels, ai.batchOrganization, memoryEcho sections
  for all locales
- Remove duplicate top-level autoLabels/batchOrganization from en.json
- Fix notebook creation: replace window.location.reload() with
  createNotebookOptimistic + router.refresh()
- Fix notebook name truncation in sidebar with min-w-0
- Remove redundant router.refresh() after note creation in page.tsx

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

keep-notes/components/create-notebook-dialog.tsx

@@ -14,6 +14,7 @@ import {
 import { Input } from '@/components/ui/input'
 import { cn } from '@/lib/utils'
 import { useLanguage } from '@/lib/i18n'
+import { useNotebooks } from '@/context/notebooks-context'
 
 const NOTEBOOK_ICONS = [
   { icon: Folder, name: 'folder' },
@@ -48,6 +49,7 @@ interface CreateNotebookDialogProps {
 export function CreateNotebookDialog({ open, onOpenChange }: CreateNotebookDialogProps) {
   const router = useRouter()
   const { t } = useLanguage()
+  const { createNotebookOptimistic } = useNotebooks()
   const [name, setName] = useState('')
   const [selectedIcon, setSelectedIcon] = useState('folder')
   const [selectedColor, setSelectedColor] = useState('#3B82F6')
@@ -61,24 +63,14 @@ export function CreateNotebookDialog({ open, onOpenChange }: CreateNotebookDialo
     setIsSubmitting(true)
 
     try {
-      const response = await fetch('/api/notebooks', {
-        method: 'POST',
-        headers: { 'Content-Type': 'application/json' },
-        body: JSON.stringify({
-          name: name.trim(),
-          icon: selectedIcon,
-          color: selectedColor,
-        }),
+      await createNotebookOptimistic({
+        name: name.trim(),
+        icon: selectedIcon,
+        color: selectedColor,
       })
-
-      if (response.ok) {
-        // Close dialog and reload
-        onOpenChange?.(false)
-        window.location.reload()
-      } else {
-        const error = await response.json()
-        console.error('Failed to create notebook:', error)
-      }
+      // Close dialog — no full page reload needed
+      onOpenChange?.(false)
+      router.refresh()
     } catch (error) {
       console.error('Failed to create notebook:', error)
     } finally {