[SCF high] Add Stellar wallet readiness preflight for demo flow

[karagozemin]

Why this matters

SCF demos can fail for simple wallet setup reasons: wrong network, unfunded testnet account, or missing Freighter access. A read-only wallet readiness preflight makes demo failures easier to diagnose.

Scope

Add a frontend preflight panel/check for Stellar wallet readiness:

• Freighter reachable;
• connected account present;
• testnet selected;
• account funded/reachable where public Horizon/RPC check is available;
• clear next-step copy for each failure state.

This should not submit transactions.

Suggested files

• frontend/src/hooks/useFreighter.ts
• frontend/src/components/NetworkMismatchBanner.tsx
• new component under frontend/src/components/
• frontend/src/config/rpc-urls.ts

Acceptance criteria

• Preflight is read-only and visible before swap submission.
• Wrong network and missing wallet states show actionable copy.
• No private keys or sensitive wallet data are logged.
• pnpm --filter @oversync/frontend build passes.

[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, please assign me

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

[omonxooo-commits]

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

Hello Maintainer. I would love to resolve this issue very quickly

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[oscar24357]

@oscar24357 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

hello i would love to work on this issue, can you please assign me to it?

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[OmniZlatoon]

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

Hi maintainer sir, I'm called Junior Brown , a full-stack and smart contract engineer building on Stellar. I specialize in designing and shipping scalable, secure systems end-to-end, from Soroban smart contracts to production-ready backend infrastructure and user-facing applications.

I’ve worked on complex architectures involving automated agents, cross-chain logic, and data indexing, focusing on reliability, performance, and clean standards. My approach is very product-driven: I don’t just build contracts, I build complete systems that solve real user problems and can scale in production.

I’m especially interested in infrastructure, security, and automation creating tools and frameworks that make it easier for other developers to build safely and efficiently on Stellar.

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[ifygreg01-best]

@ifygreg01-best has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hi Maintainer, I'd like to work on this issue by adding a read-only Stellar wallet preflight check with clear network and wallet readiness states.

Thanks!

ℹ️ Repo Maintainers: To accept this application, review their application or assign @ifygreg01-best to this issue.

[emickwrld]

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

Let me work on this!

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[dotmantissa]

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

Please, assign this issue to me.

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[Peaostrel]

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

i can handle this quickly

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