Add mutation testing to CI pipeline with Stryker

[Smartdevs17]

Description

Standard test coverage metrics dont catch missing assertions. Implement mutation testing to evaluate test quality.

Acceptance Criteria

• Stryker configuration for API and Oracle
• Mutation score gate (>80%)
• Survived mutant analysis and test improvement
• CI integration with pull request comments
• Historical mutation score tracking
• Configuration for incremental mutation testing

Technical Scope

• api/stryker.config.mjs
• .github/workflows/
• Edge: mutation testing time, equivalent mutants, Stryker performance

[krayonisaiah17-source]

@krayonisaiah17-source has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

I would like work on this task.

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[Properprogress1]

@Properprogress1 has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

Can I work on this ?

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[drips-wave]

Congratulations, @Properprogress1! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 2, 2026.

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