[Frontend] Add frontend onboarding script and README section

[floxxih]

Improve frontend onboarding with clear setup commands and troubleshooting notes.

Acceptance Criteria:

• Commands for install/dev/build/lint are documented
• Common setup failures have fixes
• Environment variable requirements are clear

[Favourof]

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

Hi, please let me work on this issue.

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

[blessinngluka]

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

I will love to work on this issue thanks

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

[meshackyaro]

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

Hi, is like to work on this. I am already familiar with the codebase and I can deliver this in due time

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

[johnsmccain]

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

i would like to work with you

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

[drips-wave]

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

🧑‍💻 @johnsmccain: 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 completed by @johnsmccain as part of the Stellar Wave Program's 5th Wave 🥳

😎 @johnsmccain: 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.