chore: remove unavailable online tutorial references

[hengyunabc]

Summary

• remove unavailable Online Tutorials links from the Chinese and English documentation
• remove the remaining README and Web Console tutorial entries
• remove the tutorial URL from the CLI banner and welcome API model
• update welcome output examples and the checked-in native-agent asset

Testing

• ./mvnw -pl core -am -Dtest=CommandExecutorImplQuietSessionTest -Dsurefire.failIfNoSpecifiedTests=false test
• cd site && npm run docs:build
• cd web-ui/arthasWebConsole && npm run build:native-agent
• cd web-ui/arthasWebConsole && npm run build

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-08-30T16:30:46.970944Z	4954d8a	PR opened

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