Add not-found and error routes for the app router

[sshdopey]

Context

There is no app-level not-found.tsx or error.tsx, so unknown routes and runtime errors use the framework defaults.

Scope

• Add branded not-found and error routes consistent with the design system.

Acceptance criteria

• Unknown routes and errors render branded pages.

Pointers

src/app/.

[TheWeirdDee]

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

Hi, I want to work on this because hitting a generic Next.js error page breaks the visual experience and feels unpolished. I'll add both not-found.tsx and error.tsx under src/app/ matching the existing design system so unknown routes and runtime errors stay on-brand.

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

[kingbitnation]

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

Hi! I'd like to work on this issue.

After reviewing the requirements, I believe it's a good match for my experience. I'll implement the requested functionality while following the project's existing architecture, coding conventions, and contribution guidelines. I'll ensure the solution is clean, well-tested, and covers all of the stated acceptance criteria, updating or adding tests where appropriate and documenting any relevant changes.

If I encounter any implementation details that need clarification, I'll communicate them early to avoid unnecessary rework.

Could this issue be assigned to me?

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

[aojomo]

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

Please, I'd like to work on this issue. I have experience contributing to open-source projects, refactoring shared code, and improving maintainability while preserving existing behavior. I'm confident I can implement this change while following the project's guidelines.

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

[Danielobito009]

@Danielobito009 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

i would love to work on this issue

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Danielobito009 to this issue.

[vickachi]

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

I'm a full-stack Software Engineer
I'd love to take this on — thanks for considering me

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

[NeduTheDev1]

@NeduTheDev1 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Please assign to me maintainer i can get it done no issues

ℹ️ Repo Maintainers: To accept this application, review their application or assign @NeduTheDev1 to this issue.

[IFEANYIBRIGHT]

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

Hi! I’m a full-stack developer with a strong blockchain background. I’d love to handle this issue and can deliver a clean, reliable solution. Kindly assign it to me.

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

[gregemax]

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

Hi Maintainer,

I’d love to work on this issue. I’ve reviewed the requirements and believe I can implement the solution according to the project’s guidelines and best practices.

If the issue is available, I’d be happy to take ownership and submit a PR for review.

Thank you for your consideration.

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