Fix: wallet account not funded shows cryptic error

[barry01-hash]

Trying to buy with an unfunded account yields an opaque failure. Detect and show 'fund your wallet first'.

[Demilade10]

@Demilade10 has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Hi I can fix this

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[damilare0813]

@damilare0813 has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

I'd be glad to handle this issue. I'll keep the implementation concise, maintainable, and well-documented

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[ExcelDsigN-tech]

@ExcelDsigN-tech has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

I'm a full-stack developer with hands-on experience across Next.js, Node.js, NestJS, React, and TypeScript, and I also specialize in smart contract development using Rust and Soroban. I build end-to-end, from polished frontends to robust backends to on-chain logic, with a strong focus on clean, maintainable code that works in production, not just in isolation. I communicate progress consistently and keep things fully transparent throughout. I'm confident I can deliver within 12 hours.

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