Bring docker-compose.yml back in line with the env contract #194

Background

The dev compose file is stale against .env.example. It passes only the legacy names STELLAR_RPC_URL and CONTRACT_IDS, and omits STELLAR_NETWORK, NETWORKS, SOROBAN_RPC_URL, SAC_CONTRACT_IDS, DIRECT_DATABASE_URL, RETENTION_DAYS and the entire Redis block — so docker compose up cannot produce a dual-network stack and cannot exercise the cache layer at all. It also still carries the obsolete version: "3.9" key.

This is distinct from issue #63, which is about the integration-test compose file; that one exists and works.

Acceptance criteria

• Env keys match .env.example; legacy names removed, or kept only as documented aliases
• An optional redis service so CACHE_ENABLED=true works out of the box
• version: removed
• docker compose config is warning-free and docker compose up reaches a healthy /readyz on testnet with no extra env
• README "Start Postgres" / "Start Wraith" steps updated to match

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.

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