[Enhancement] Add env.token(symbol) accessor to retrieve registered MockTokens by name after build()

[ekelemepraise-code]

Summary

Tokens registered via .with_token("USDC", 6) during builder configuration are inaccessible after build() completes. Users must re-construct the token or store it before the builder is consumed.

let env = MockEnv::builder()
    .with_token("USDC", 6)
    .build();

// Currently impossible — no way to get the USDC token back
let usdc = env.token("USDC"); // method does not exist

Proposed API

impl MockEnv {
    pub fn token(&self, symbol: &str) -> MockToken { ... }
    pub fn token_opt(&self, symbol: &str) -> Option<MockToken> { ... }
}

Implementation

• MockEnv should store a HashMap<String, MockToken> populated during build()
• token() panics with a clear message if the symbol was not registered
• token_opt() returns None gracefully

Acceptance Criteria

• env.token("USDC") works after with_token("USDC", 6).build()
• Clear panic message when symbol not found
• Works alongside manually constructed MockToken::new() (separate code path)
• Exported via prelude

[RaymondAbiola]

@RaymondAbiola has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

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

The requirements are clear, and I'm comfortable working across different parts of the stack, including frontend, backend, smart contracts, and developer tooling. I'll follow the project's conventions, keep the implementation clean, and ensure it's properly tested before submitting.

Thanks!

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[onakijames-droid]

@onakijames-droid has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

Hi maintainer... I'll work on this issue and submit a PR for it ASAP

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[Olamidepy]

@Olamidepy has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

Kindly assign boss

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[chukwunazannakenyi-netizen]

@chukwunazannakenyi-netizen has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

hoi mAINTAINER i will like tio workon this issue please

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[CHKM001]

@CHKM001 has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

I WANT TO GET THIS ISSUE DONE
BUT IF NOT GIVE THAT OLAMIDE GUY
I'VE SEEN HIS CODEE

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[Mamavee001]

@Mamavee001 has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

Hello can i work on this asap

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[drips-wave]

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

🧑‍💻 @Olamidepy: 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.

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