🛡️ Sentinel: Fix actions/checkout version in CI/CD workflows

[google-labs-jules]

Corrected the invalid and non-existent version of the actions/checkout GitHub Action from @v7 to @v4 in check.yml and docs.yml, ensuring workflow stability and security.

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PR created automatically by Jules for task 2270061226744450343 started by @amrabed

[google-labs-jules]

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud