[P3] Reject zero and negative amounts in DonatePoolDto

[cyber-punk112]

Description

src/pools/dto/donate-pool.dto.ts's amount field only has @IsNumberString() and @IsNotEmpty(). class-validator's IsNumberString accepts negative numbers and "0" by default, so POST /pools/:id/donate with { "amount": "-100" } or { "amount": "0" } currently passes validation and reaches ContractService.buildDonateTransaction, which will build a nonsensical unsigned transaction for the caller to sign.

Deliverables

• Add a custom validator (or @Matches(/^[1-9][0-9]*$/)) to DonatePoolDto.amount that rejects zero, negative, and non-integer values
• Add tests confirming amount: "0" and amount: "-5" are rejected with 400
• npm run build passes

[timmyp10111]

@timmyp10111 has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Please assign this issue to me

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[beetecch]

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

Hi! I’d like to take on this issue. I’ll tighten DonatePoolDto.amount validation to reject zero, negative, and non-integer values before they reach the contract layer. I’ll add tests confirming invalid amounts return 400 and verify the project still passes npm run build.

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