feat: Complete internationalization and code cleanup

## Translation Files
- Add 11 new language files (es, de, pt, ru, zh, ja, ko, ar, hi, nl, pl)
- Add 100+ missing translation keys across all 15 languages
- New sections: notebook, pagination, ai.batchOrganization, ai.autoLabels
- Update nav section with workspace, quickAccess, myLibrary keys

## Component Updates
- Update 15+ components to use translation keys instead of hardcoded text
- Components: notebook dialogs, sidebar, header, note-input, ghost-tags, etc.
- Replace 80+ hardcoded English/French strings with t() calls
- Ensure consistent UI across all supported languages

## Code Quality
- Remove 77+ console.log statements from codebase
- Clean up API routes, components, hooks, and services
- Keep only essential error handling (no debugging logs)

## UI/UX Improvements
- Update Keep logo to yellow post-it style (from-yellow-400 to-amber-500)
- Change selection colors to #FEF3C6 (notebooks) and #EFB162 (nav items)
- Make "+" button permanently visible in notebooks section
- Fix grammar and syntax errors in multiple components

## Bug Fixes
- Fix JSON syntax errors in it.json, nl.json, pl.json, zh.json
- Fix syntax errors in notebook-suggestion-toast.tsx
- Fix syntax errors in use-auto-tagging.ts
- Fix syntax errors in paragraph-refactor.service.ts
- Fix duplicate "fusion" section in nl.json

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

Ou une version plus courte si vous préférez :

feat(i18n): Add 15 languages, remove logs, update UI components

- Create 11 new translation files (es, de, pt, ru, zh, ja, ko, ar, hi, nl, pl)
- Add 100+ translation keys: notebook, pagination, AI features
- Update 15+ components to use translations (80+ strings)
- Remove 77+ console.log statements from codebase
- Fix JSON syntax errors in 4 translation files
- Fix component syntax errors (toast, hooks, services)
- Update logo to yellow post-it style
- Change selection colors (#FEF3C6, #EFB162)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

keep-notes/components/register-form.tsx

@@ -6,24 +6,27 @@ import { register } from '@/app/actions/register';
 import { Button } from '@/components/ui/button';
 import { Input } from '@/components/ui/input';
 import Link from 'next/link';
+import { useLanguage } from '@/lib/i18n';
 
 function RegisterButton() {
   const { pending } = useFormStatus();
+  const { t } = useLanguage();
   return (
     <Button className="w-full mt-4" aria-disabled={pending}>
-      Register
+      {t('auth.signUp')}
     </Button>
   );
 }
 
 export function RegisterForm() {
   const [errorMessage, dispatch] = useActionState(register, undefined);
+  const { t } = useLanguage();
 
   return (
     <form action={dispatch} className="space-y-3">
       <div className="flex-1 rounded-lg bg-gray-50 px-6 pb-4 pt-8">
         <h1 className="mb-3 text-2xl font-bold">
-          Create an account.
+          {t('auth.createAccount')}
         </h1>
         <div className="w-full">
           <div>
@@ -31,7 +34,7 @@ export function RegisterForm() {
               className="mb-3 mt-5 block text-xs font-medium text-gray-900"
               htmlFor="name"
             >
-              Name
+              {t('auth.name')}
             </label>
             <div className="relative">
               <Input
@@ -39,7 +42,7 @@ export function RegisterForm() {
                 id="name"
                 type="text"
                 name="name"
-                placeholder="Enter your name"
+                placeholder={t('auth.namePlaceholder')}
                 required
               />
             </div>
@@ -49,7 +52,7 @@ export function RegisterForm() {
               className="mb-3 mt-5 block text-xs font-medium text-gray-900"
               htmlFor="email"
             >
-              Email
+              {t('auth.email')}
             </label>
             <div className="relative">
               <Input
@@ -57,7 +60,7 @@ export function RegisterForm() {
                 id="email"
                 type="email"
                 name="email"
-                placeholder="Enter your email address"
+                placeholder={t('auth.emailPlaceholder')}
                 required
               />
             </div>
@@ -67,7 +70,7 @@ export function RegisterForm() {
               className="mb-3 mt-5 block text-xs font-medium text-gray-900"
               htmlFor="password"
             >
-              Password
+              {t('auth.password')}
             </label>
             <div className="relative">
               <Input
@@ -75,7 +78,7 @@ export function RegisterForm() {
                 id="password"
                 type="password"
                 name="password"
-                placeholder="Enter password (min 6 chars)"
+                placeholder={t('auth.passwordMinChars')}
                 required
                 minLength={6}
               />
@@ -93,9 +96,9 @@ export function RegisterForm() {
           )}
         </div>
         <div className="mt-4 text-center text-sm">
-          Already have an account?{' '}
+          {t('auth.hasAccount')}{' '}
           <Link href="/login" className="underline">
-            Log in
+            {t('auth.signIn')}
           </Link>
         </div>
       </div>