Adds editServer.test.ts with 8 tests covering: RPC error returns 503 with
nonce intact, invalid signature returns 401 with nonce intact, valid
signature consumes nonce and writes metadata, already-used nonce rejected,
rate-limit DoS mechanism, cross-wallet isolation, 10 invalid-sig requests
do not freeze the wallet, non-creator nonce requests do not spend the
wallet bucket.
Test infrastructure: tsx dev dependency, tsconfig.test.json for path-alias
mocking of @/lib/db and @/lib/chain, db-mock.ts and chain-mock.ts for
mocked DB and RPC, test-loader.mjs for @/ path resolution. The test script
uses tsx with react-server conditions; test:unit preserves the original
node-only runner for pure-logic tests.
