fix: 完善首页和详情页国际化实现

- 首页 hero 区域标题和描述使用 i18n 翻译
- 首页 "BROWSE BY TAGS" 和 "FEATURED PROJECTS" 使用 i18n 翻译
- 详情页 "BACK TO PROJECTS" 使用 i18n 翻译
- 添加缺失的中英文翻译键

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

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

src/app/[locale]/projects/[id]/page.tsx

@@ -1,4 +1,5 @@
 import { notFound } from 'next/navigation'
+import { getTranslations } from 'next-intl/server'
 import { getProjectBySlug, getProjects } from '@/hooks/useProjects'
 import { ProjectDetail } from '@/components/project/ProjectDetail'
 import { ProjectSidebar } from '@/components/project/ProjectSidebar'
@@ -13,6 +14,7 @@ export default async function ProjectDetailPage({
 }: ProjectDetailPageProps) {
   const resolvedParams = await params
   const { locale, id } = resolvedParams
+  const tProject = await getTranslations('project')
 
   // Get project by slug
   const project = await getProjectBySlug(id)
@@ -43,7 +45,7 @@ export default async function ProjectDetailPage({
             <span className="material-icons text-base mr-1 group-hover:-translate-x-1 transition-transform">
               arrow_back
             </span>
-            BACK TO PROJECTS
+            {tProject('backToProjects')}
           </a>
         </div>