feat(log): implement Pino-based logger

[sheplu]

First real implementation of @express/log, replacing the hello() placeholder.

API

const logger = createLogger({ service: "my-api", version: "1.2.3" });
logger.info("request received");
logger.child({ req_id: "abc" }).info({ user_id: "u-1" }, "authenticated");

• Standard base fields on every line: service, version, env, host, pid, runtime, logger.name
• Reserved correlation fields (req_id, trace_id, span_id, …) populated by consumers via logger.child() — not set by core
• Default redaction (auth headers, passwords, tokens, secrets) with mergeable overrides and remove: true support
• Transport: NDJSON to stdout in production, pino-pretty to stderr in development
• Error serializer wraps pino.stdSerializers.err and adds Node err.code

Tests

• unit: pure-function tests, 100% line coverage
• integration: factory → capture stream → JSON parse
• e2e: subprocess smoke tests against the built dist/

CI

Adds e2e and manifest jobs that reuse the build artifact.

Out of scope

Express middleware, OTel bindings, AsyncLocalStorage, file transports — follow-up work.