v0.0.28

• SSE silent-stall fix (Layer 1, qfg-47c2.7). The SDK now wraps the eventsource library's
  underlying fetch with an AbortController whose deadline resets on every chunk. If no chunk
  arrives within sseReadDeadlineMs (default 90s = 3x the 30s server heartbeat), the socket is
  dropped and the eventsource library reconnects. Previously the SDK relied on the OS TCP timeout
  (often 2+ hours), so a silent server-side stall could go unnoticed for hours.
• Polling is now a fallback, not a parallel stream (Layer 2, qfg-47c2.7). New options
  fallbackPollEnabled (default true) and fallbackPollIntervalMs (default 60000) configure an
  HTTP poll that only runs when SSE is unavailable — either because the initial SSE connection
  failed (DNS, TLS, HTTP error before any successful onopen) or because SSE has been disconnected
  for >= 2x the poll interval (default 120s) without recovering. When SSE recovers (next successful
  connected transition), the fallback poller stops. The previous enablePolling / pollInterval
  options are deprecated and now map onto the new options with a deprecation warning; the behavior
  changes — those options previously ran a parallel poller on top of SSE (double bandwidth, no
  reconcile logic). Alpha-phase, no semver hold per resolved Q1 in
  project/plans/sdk-hardening-and-verification.md.
• Boot log. init() now emits a single info-level log line announcing the chosen update channel
  (SSE-with-fallback / SSE-only / polling-only / none) so deployers can see the new default at
  startup.
• Health getters (qfg-47c2.14). New public methods lastSuccessfulRefresh() and
  connectionState() expose diagnostic state for composing custom freshness checks. The aggregate
  ConnectionState type (initializing / connected / disconnected / falling_back) is now
  exported. Diagnostic only — see the README on why these must not be wired into a k8s liveness
  probe.
• datadir: exclude schemas/ and reject empty-key files (qfg-2inx). Files under a workspace's
  schemas/ directory are no longer loaded as configs, and a config file whose key is empty is
  rejected with a clear error instead of being silently mis-keyed.
• Chaos harness (qfg-47c2.7, qfg-47c2.29, qfg-47c2.32, qfg-mzg2). sdk-node ships a chaos-test
  runner under chaos/ (invoked via npm run test:chaos / npm run chaos) that drives the
  cross-SDK scenarios in integration-test-data/chaos/scenarios/ against the SDK via toxiproxy.
  Scenario 07 switched to proxy-disable instead of the limit_data toxic; the runner identifies its
  session to the shared chaos lock; and scripts/run-chaos.sh boots api-delivery + toxiproxy and
  tears them down on exit. The chaos smoke suite now runs on every push and PR and gates the release
  workflow.
• Dependencies. eventsource ^3.0.0 → ^4.1.0; dev deps typescript ^5.3.0 → ^6.0.3
  (tsconfig gains types: ["node"] + ignoreDeprecations: "6.0" for the TS 6 lib/baseUrl changes),
  vitest ^1.0.0 → ^4.1.6 (CI test-matrix floor raised to Node 20.19.0 for vitest 4's rolldown
  binding), pino 9.14.0 → 10.3.1, @types/node ^20.11.0 → ^25.6.0. CI actions
  actions/checkout → v6.0.2 and actions/setup-node → v6.4.0.