[BE-62] Implement Stellar tokenization API — fractional ownership token management

[yusuftomilola]

Overview

The assetsup contract supports tokenization — splitting an asset into fractional tokens that can be held by multiple investors. This issue exposes the tokenization contract functions as REST API endpoints. Enables the tokenization UI (FE-43) and investor portal (FE-44).

Context

• Depends on BE-60 (StellarService) and BE-61 (asset must be registered on-chain first)
• Contract source: contracts/assetsup/src/tokenization.rs — review tokenize(), transfer_tokens(), lock_tokens(), unlock_tokens() function signatures
• Token holders and balances are stored on-chain — the backend reads them via contract data queries

Acceptance Criteria

• POST /stellar/assets/:id/tokenize body: { totalTokens: number, pricePerToken: number, lockPeriodDays?: number } — calls contract tokenize(), stores tokenization config on the Asset entity (isTokenized: boolean, totalTokens, tokenPrice)
• GET /stellar/assets/:id/tokens — queries on-chain token holders and balances, returns: { totalTokens, circulatingTokens, holders: [{ address, balance, percentage }] }
• POST /stellar/assets/:id/tokens/transfer body: { toAddress: string, amount: number } — calls contract transfer_tokens()
• POST /stellar/assets/:id/tokens/lock and POST /stellar/assets/:id/tokens/unlock — calls contract lock/unlock functions
• Add isTokenized, totalTokens (nullable), tokenPrice (nullable decimal) to Asset entity

[Bojest001]

@Bojest001 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hi maintainer I will like to work on this issue

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Bojest001 to this issue.

[RUKAYAT-CODER]

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

Hi, am a full stack developer. can i take up this task?

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

[drips-wave]

Congratulations, @RUKAYAT-CODER! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 30, 2026.

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