feat(projects): add project tags and improve project cards layout

- Add project type tags (business, opensource, personal) to project cards
- Update i18n translations for new project tags and visit/demo labels
- Improve tech stack indicators styling with unified gray theme
- Simplify project card footer links to use translation labels
- Update project descriptions and tech stack details

src/i18n/ui.ts

@@ -17,7 +17,12 @@ export const ui = {
     'site.description': 'Full Stack Developer specializing in React, Node.js, and modern web technologies',
     'hero.githubLink': 'GitHub Profile',
     'hero.linkedinLink': 'LinkedIn Profile',
-    'footer.rights': 'All rights reserved'
+    'footer.rights': 'All rights reserved',
+    'project.tag.business': 'Business Project',
+    'project.tag.opensource': 'Open Source',
+    'project.tag.personal': 'Personal Product',
+    'project.visit': 'Visit',
+    'project.demo': 'Live Demo'
     // Projects and services content has been inlined into respective page files
     // to reduce reliance on the translation system and improve maintainability
   },
@@ -31,7 +36,12 @@ export const ui = {
     'site.description': '专注于 React、Node.js 和现代 Web 技术的全栈开发者',
     'hero.githubLink': 'GitHub 主页',
     'hero.linkedinLink': 'LinkedIn 主页',
-    'footer.rights': '版权所有'
+    'footer.rights': '版权所有',
+    'project.tag.business': '商业项目',
+    'project.tag.opensource': '开源项目',
+    'project.tag.personal': '个人产品',
+    'project.visit': '访问',
+    'project.demo': '在线演示'
     // Projects and services content has been inlined into respective page files
     // to reduce reliance on the translation system and improve maintainability
   }