Add backend seed script for local dev

[aji70]

Description (Backend)
Provide deterministic seed data for development/testing.

Tasks

• Add seed command
• Insert mock creators/fans/plans/content
• Document usage

Additional Requirements

• Keep seed idempotent

Acceptance Criteria

• Dev environment can be seeded quickly
• Seed reruns do not duplicate data

[munyanezaarmel]

@munyanezaarmel has applied to work on this issue as part of the Stellar Wave Program's 3rd wave.

I would like to work on this because it is the kind of engineering challenge I enjoy.
I am a fullstack developer with 4 years of experience across Next.js, React, Node.js, Python, Java, Rust, and Soroban SDK and have dealt with smart contract development, auth patterns, share accounting, SAC tokens, wallet integration, and Soroban's storage model. I can deliver within the given timeframe with clean code, solid test coverage, and proper documentation

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

[drips-wave]

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

🧑‍💻 @munyanezaarmel: 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 🌊

[drips-wave]

This issue has been marked as completed by a Drips Wave moderator for @munyanezaarmel as part of the Stellar Wave Program's 3rd Wave 🥳

Moderator's reason: [Auto-assessed] PR #511 in MyFanss/MyFans has been open for over 4 days without maintainer objections. The contribution fully addresses the requirements of Issue #338, including the implementation of an idempotent seed script, the necessary package.json changes, and clear documentation in the README.

😎 @munyanezaarmel: 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.

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

ℹ️ Note: This issue was marked complete via moderation. Points were issued even though the GitHub issue remains open.