fix(frontend): remove locale-dependent routing and migrate to centralized locale-aware router

- Replaced `next/navigation` with `@/lib/i18n/routing` across components, pages, and tests.
- Removed redundant `locale` props from `ProjectWizard` and related pages.
- Updated navigation to exclude explicit `locale` in paths.
- Refactored tests to use mocks from `next-intl/navigation`.

frontend/src/components/projects/ProjectDashboard.tsx

@@ -10,7 +10,7 @@
 'use client';
 
 import { useCallback, useMemo, useState } from 'react';
-import { useRouter } from 'next/navigation';
+import { useRouter } from '@/lib/i18n/routing';
 import { AlertCircle, RefreshCw } from 'lucide-react';
 import { cn } from '@/lib/utils';
 import { Alert, AlertDescription, AlertTitle } from '@/components/ui/alert';

frontend/src/components/projects/wizard/ProjectWizard.tsx

@@ -8,7 +8,7 @@
  */
 
 import { useState } from 'react';
-import { useRouter } from 'next/navigation';
+import { useRouter } from '@/lib/i18n/routing';
 import { ArrowLeft, ArrowRight, Check, CheckCircle2, Loader2 } from 'lucide-react';
 import { useMutation } from '@tanstack/react-query';
 
@@ -49,11 +49,10 @@ interface ProjectResponse {
 }
 
 interface ProjectWizardProps {
-  locale: string;
   className?: string;
 }
 
-export function ProjectWizard({ locale, className }: ProjectWizardProps) {
+export function ProjectWizard({ className }: ProjectWizardProps) {
   const router = useRouter();
   const [isCreated, setIsCreated] = useState(false);
 
@@ -106,9 +105,9 @@ export function ProjectWizard({ locale, className }: ProjectWizardProps) {
   const handleGoToProject = () => {
     // Navigate to project dashboard - using slug from successful creation
     if (createProjectMutation.data) {
-      router.push(`/${locale}/projects/${createProjectMutation.data.slug}`);
+      router.push(`/projects/${createProjectMutation.data.slug}`);
     } else {
-      router.push(`/${locale}/projects`);
+      router.push(`/projects`);
     }
   };