Milestone Escrow

[Dev-journals]

Summary

Adds backend support for scholarship milestone escrow creation and release. When a scholarship_treasury.execute_proposal event occurs, the server now records the escrow on-chain and persists it in the new escrows table. Milestone approval is also wired to call release_tranche on active escrows, while existing reclaim logic remains intact.

Type of Change

• Bug fix
• New feature
• Smart contract change
• Documentation
• Breaking change
• Other (please describe)

Checklist

• Tests added or updated
• No hardcoded secrets or private keys
• If contract change: cargo test passes
• If frontend change: npm run typecheck passes
• If backend change: npm test passes
• Related issues linked (Closes #...)
• Self-review completed
• Code follows project style guidelines

Screenshots (if applicable)

Testing

cd server && npm test -- --runInBand src/controllers/admin-milestones.controller.test.ts src/tests/admin-milestones.test.ts

Result:

2 test suites passed
35 tests passed

Additional Notes

• Added 028_create_escrows.sql and undo migration.
• Extended stellar-contract.service.ts with escrow creation and tranche release helpers.
• Added event handling in event-indexer.service.ts for proposal_executed.
• Updated admin-milestones.controller.ts to release escrow tranches on approved milestones.

Closes #1016

@Anuoluwapo25 Kindly review and merge

[Anuoluwapo25]

@Dev-journals it's remaining one more check