feat: Update images with Unsplash (hero + illustrations), fix UX/UI, add animations

- Replace MiniMax images with Unsplash (free commercial use)
- Hero images: marketing, AI automation, tech consult, web dev, about-us
- Illustrations: different from heroes for all 4 service pages
- Fix ตัวอย่างการใช้งาน section on marketing-automation
- Update about-us with hero image
- All images stored locally (not hotlinks)

.gitignore

@@ -16,6 +16,7 @@ pnpm-debug.log*
 # environment variables
 .env
 .env.production
+.env.local
 
 # macOS-specific files
 .DS_Store