Add npm run db:seed with deterministic fixtures #193

Background

There is no seed anywhere: prisma/ holds only migrations/ and schema.prisma, scripts/ holds one backfill script, and package.json has no seed entry. A contributor who follows the README Quick Start gets an empty database and must wait for live testnet events on a watched contract before any endpoint returns a row.

Fixtures already exist but are locked inside the vitest-only integration suite (tests/integration/fixtures.ts) and src/__tests__/fixtures/events.json.

Acceptance criteria

• npm run db:seed inserts deterministic TokenTransfer / NftTransfer / AccountSummary rows across at least two addresses and two contracts
• Rows are tagged network, and the seed accepts a --network flag
• Running it twice does not duplicate
• The README Quick Start gains a "seed and query" step whose sample output is real
• Ideally the integration harness reuses the same fixture module rather than keeping a second copy

Drips Wave · Complexity: Easy · 100 points

How this repo is laid out

Wraith is a Soroban incoming-transfer indexer: it fills the gap Horizon leaves for SAC/SEP-41 token events by recipient address. Roughly 14k lines under src/, REST + GraphQL + WebSocket, Postgres via Prisma, deployed on Render.

• Unit tests are jest (src/**/__tests__, tests/*.test.ts), with a coverage gate.
• Integration tests are vitest (tests/integration/, vitest.integration.config.ts, Docker).
• Don't mix the two runners in one file.

Known state of main before you start

tsc --noEmit and the unit suite are green. The Integration tests CI job is red, and so is Load test — both predate this batch. Open PRs #177 and #178 address them. If the integration job is red when you open a PR, that is not your fault; say so in the PR and carry on.

Four modules are shipped, closed as done, and imported by nothing: src/indexer/checkpoint.ts, src/ingest/reorg.ts, src/middleware/opa.ts, and src/api/candles.ts + src/workers/ohlc-refresh.ts. So the live indexer today has no reorg handling and no atomic checkpointing, despite both features being closed. Two issues below start unpicking that — don't assume a closed issue means a wired feature.

Ground rules

• Every PR needs a test that fails before the change and passes after, unless the issue says otherwise.
• Don't widen a Prometheus label to something unbounded — addresses and contract ids must never become label values.
• Nothing may log or return a raw database error, a connection string, or a provider URL.
• Don't reformat a file you're changing. A diff that is 90% whitespace hides the 10% that matters.

Required: Before submitting, join the contributor Telegram so your work can be tracked and counted toward the Stellar Wave: https://t.me/+fxHXq8f1SwlkZDBk