Add announcement for KubeCon + CloudNativeCon Japan 2026 and update metrics - #648

Changed pages include:

• index.html - view
• 404.html - view
• blog.html - view
• case-studies.html - view
• changelog.html - view
• community.html - view
• docs.html - view
• search.html - view
• tutorials.html - view
• zh/index.html - view

There are more changes not included in the list