feat(backend): Crowdfund Vault Sync Worker — contributions, milestones, refund windows (#711)

[Mormentz]

Summary

Closes #711

Adds a backend worker that tracks crowdfund vault Soroban events on testnet and materializes them into Postgres:

• Deposits / contributions → crowdfund_vault_projects, crowdfund_vault_contributors
• Milestone approvals → crowdfund_vault_milestones
• Refund window / reversals → project status + contribution adjustments (ProjectExpiredEvent, ContributionRefundedEvent, ContributionClawedBackEvent)

Events flow through the existing soroban-events BullMQ pipeline (webhook ingest) and an optional RPC poller (getEvents) when STELLAR_CONTRACT_CROWDFUND_VAULT is configured.

Design

• Idempotency: UNIQUE (txHash, eventIndex) on raw events; BullMQ jobId unchanged
• Ledger sequencing: skip materialization when incomingLedgerSeq < stored lastLedgerSeq (same pattern as project_registry)
• Replay-safe: re-delivering the same event is a no-op after the raw row exists

Schema

New migration: 1780200000000-CreateCrowdfundVaultSync.ts

Test plan

• npx jest --testPathPattern=crowdfund-vault-sync (6 tests)
• npm run build
• Run migration: npm run migration:run (from apps/backend)
• Set STELLAR_CONTRACT_CROWDFUND_VAULT + STELLAR_SOROBAN_RPC_URL on testnet
• POST a sample DepositEvent to /soroban-events/ingest and verify rows in crowdfund_vault_* tables
• Confirm cron poller queues events when contract ID is set (check logs)

Notes

• CrowdfundService remains in-memory for now; API can be wired to crowdfund_vault_projects in a follow-up.
• Project registry routing now prefers config.stellar.contracts.projectRegistry over the legacy PROJECT_REGISTRY_CONTRACT_ID env var.

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[Cedarich]

@Mormentz please fix workflow