Combine nonces and vaults table

[dkuthoore]

NOTE

Change base branch to main before merging, i built this branch off of dk/assignDeposit, assuming it would be merged first.

Summary

This PR merges the standalone nonces table into the vaults table by adding a NOT NULL DEFAULT 0 nonce column and enforcing that every vault always has at least one controller. All reads/writes of nonce now use vaults.nonce, and the legacy nonces table and its index are removed. API behavior is preserved, with stricter validation and clearer errors.

Changes

• Schema and migrations

  • Add nonce INTEGER NOT NULL DEFAULT 0 to vaults.
  • Add CHECK constraint vaults_controllers_nonempty to ensure controllers are never empty.
  • Migration migrations/4_merge_nonces_into_vaults.sh:
    • Backfills vaults.nonce from legacy nonces if it exists.
    • Drops unique_lower_vault_nonces and the nonces table.
  • Update migrations/1_start.sh to remove creation of nonces and related index/lowercasing.

• App logic

  • Controllers (src/controllers.ts):
    • /nonce/:vault GET now reads from vaults.nonce.
    • /nonce/:vault POST now updates vaults.nonce; returns 404 if the vault doesn’t exist.
    • Metrics vault count now uses SELECT COUNT(*) FROM vaults.
  • Proposer (src/proposer.ts):
    • Reads nonce from vaults.nonce.
    • Updates vaults.nonce only; no row creation. Logs a warning if the vault is missing.
  • Vault utilities (src/utils/vaults.ts):
    • updateVaultControllers rejects empty controller arrays.
    • removeControllerFromVault prevents removing the last controller; reverts the change and throws a descriptive error.
  • DB config (src/config/dbSettings.ts): removed nonces from REQUIRED_TABLES.

• Setup scripts and tests

  • scripts/shared/db-setup.js: remove nonces table and index; add vaults.nonce with default 0; update drop/verify/log messages; keep balances lowercasing.
  • scripts/setup-db.js and scripts/setup-test-db.js: update help text to reflect vaults storing nonce.
  • test/helpers/testServer.ts: remove nonces from TRUNCATE list.
  • Integration tests (test/integration/vaults.db.test.ts):
    • Update test to assert that removing the last controller is rejected.
    • Add test for nonce default (0) and updating behavior.

Deployment notes

• Run migrations/4_merge_nonces_into_vaults.sh :
  • Adds vaults.nonce, enforces non-empty controllers, backfills from nonces, then drops the legacy table and index.
• Ensure no flows attempt to set nonce for non-existent vaults (now enforced with 404 / warning).

[KagemniKarimu]

Looks good to me! nice work.