docs: mention IDE debugging launchers

[vibhor-aggr]

Summary

• Add a short launch-configuration section to the 4.x and 5.x debugging guides.
• Clarify that DEBUG can be set by IDE/process launchers, not only terminal commands.
• Link to the official VS Code Node.js debugging documentation as one example.

Fixes #1380.

Verification

• npx prettier --check src/content/docs/en/4x/guide/debugging.mdx src/content/docs/en/5x/guide/debugging.mdx
• npx cspell src/content/docs/en/4x/guide/debugging.mdx src/content/docs/en/5x/guide/debugging.mdx
• git diff --check
• npm run lint
• npm run build

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