docs: update marketplace publishing and creator center guides

[Ill-donut]

Summary

• consolidate Marketplace preparation, submission, and review into one submission guide
• add task-focused Creator Center guidance for viewing plugin performance and feedback, sharing access with organization members, and claiming missing organization plugins
• synchronize Cloud and Self-host references, navigation, and redirects in English, Chinese, and Japanese
• add an illustration showing how a Plugin ID maps to an organization handle

Validation

• python3 tools/check-links.py --internal
• formatting checks for English, Chinese, and Japanese Marketplace pages
• terminology verification against Creator Center UI at dify-marketplace d58368c2
• git diff --check

Status

Draft for content and structure review. This PR targets the marketplace-doc collaboration branch, not main.

Tracking: DC-259