v0.2.0 — single-flight, OTel, integration tests

First minor bump. Three differentiators land in this release.

Added

• Single-flight refresh lock (singleFlight: true,
  singleFlightLockTtlSec: 10). Opt-in stampede protection at the SWR
  boundary. Uses the bundled refresh-tag-lock.lua script over a Redis
  SETNX-style lock; only the leader's stale read triggers the
  background refresh, all others fall through to the follower path.
  Two new MetricEvent types (cache.stale.refresh.leader,
  cache.stale.refresh.follower) appear in onMetric so operators can
  verify leadership balance. Lock-acquisition failures are best-effort
  and always degrade to the safe follower path; the stale entry is
  served regardless.
• OpenTelemetry reference adapter at
  examples/opentelemetry/.
  The library itself stays dependency-free; the example shows the
  smallest viable wiring of onMetric to OTel counters and histograms
  with bounded cardinality (no cache keys or tag names emitted as
  attributes).
• Integration tests against real Redis 7 (21 scenarios) covering
  both redis@5 and ioredis adapters. Each adapter runs the same
  test grid so a regression in either client library is pinpointed
  immediately. New scripts: npm run test:integration,
  npm run test:integration:up / :down for the docker-compose
  fixture.
• CI integration job runs the integration suite against an
  ephemeral Redis 7 service container on every PR.
• GitHub Actions OIDC publish path in .github/workflows/release.yml
  with id-token: write and NPM_CONFIG_PROVENANCE=true. Currently
  scoped to workflow_dispatch trigger so the first GHA-driven publish
  can be observed; flip to push: main once the changesets cadence
  stabilizes. Tarballs published from the workflow will land on npm
  with verified provenance.

Changed

• MetricEventType union grew three new entries:
  cache.stale.refresh.leader, cache.stale.refresh.follower,
  cache.stale.refresh.skipped. The legacy cache.stale event still
  fires when singleFlight is off (default).
• HandlerState now carries an instanceId (read from HOSTNAME /
  ECS_TASK_ID / pid-<pid>) and embeds it in every refresh-lock
  acquisition for operator-side observability.

Compatibility

• No breaking changes. All existing 0.1.x configurations continue to
  work; singleFlight defaults to false.

Verified

• 72 unit tests (8 files) + 21 integration tests (1 file × 21 scenarios)
  all green.
• arethetypeswrong: 28/28 cells green.
• publint: clean.

Install: npm install @leejpsd/nextjs-cache-handler
npm: https://www.npmjs.com/package/@leejpsd/nextjs-cache-handler/v/0.2.0