docs: add PowerShell Pages deployment cleanup example

[AlexMnrs]

Summary

• add tabs for the Pages deployment cleanup script
• keep the existing macOS/Linux shell example
• add a Windows PowerShell version that uses ConvertFrom-Json instead of jq

Closes #31753

Validation

• git diff --check

Note: I attempted pnpm exec prettier --check src/content/docs/pages/platform/known-issues.mdx, but it timed out locally after the dependency install did not complete within two minutes. I stopped the stale local processes and did not keep generated dependency files.

[cloudflare-docs-bot]

Review

✅ No issues found in commit 5330e05.

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