Backend Posts: Add DTO validation tests for invalid input

[aji70]

Description (Backend)

Backend module Posts (posts). Add DTO validation tests for invalid input.

Tasks

• Implement the change in the relevant code paths
• Wire or persist state where the feature touches runtime behavior
• Add tests (unit, integration, and/or contract/UI as appropriate)

Additional Requirements

• Handle stale, disconnected, or invalid states gracefully where applicable
• Follow existing patterns in this repository (linting, modules, security)

Acceptance Criteria

• Behavior is covered by tests and documented where APIs changed
• No regressions in closely related user or API flows

[MissBlue00]

@MissBlue00 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hi can I be assigned to this issue?

ℹ️ Repo Maintainers: To accept this application, review their application or assign @MissBlue00 to this issue.

[Creed1759]

@Creed1759 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

I'm a software dev, may I take on this issue if it's still available?

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Creed1759 to this issue.

[drips-wave]

Congratulations, @Creed1759! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 30, 2026.

🧑‍💻 @Creed1759: Please resolve the issue such that the repo's maintainers have enough time to review your contribution before the due date. You'll earn Points for completing the issue on-time, which will make you eligible for a share of the Stellar Wave Program's reward pool.

Warning

When opening a PR, please link it to this issue to ensure it gets tracked accurately. Points are awarded when this issue is marked as completed by the maintainer.

🤠 Repo maintainers: Please keep an eye on the contributor's progress and review their work before the due date. You can manage this issue, including adjusting its complexity and points, here.

🌊 Happy Wave 🌊

[grantfox-oss]

🦊 GrantFox — @Creed1759 has been assigned to this issue as part of the Official Campaign campaign!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #1000)
2. Your PR will be reviewed by the MyFanss maintainers

Good luck! Track your progress on GrantFox.

[grantfox-oss]

🎉 This issue has been marked as completed on GrantFox as part of the Official Campaign campaign!

@Creed1759's PR #1319 was approved and merged by @aji70.

🏆 @Creed1759: You earned 35 FoxPoints for this contribution! Your current tier: Explorer (121 total points). Track your full progress on GrantFox.

👏 Great work, @Creed1759! Keep contributing to MyFanss.

[drips-wave]

This issue has been completed by @Creed1759 as part of the Stellar Wave Program's 6th Wave 🥳

😎 @Creed1759: You earned 200 Points for completing this issue! After the current Wave ends, you'll be eligible for a percentage of the Wave's reward pool based on the percentage of total points you've earned. Learn more here. You can also Leave a review to share your experience working on this issue.

🧑‍💻 Repo maintainers: How'd the contributor do? Leave a review to share your experience working with them.