v1.19.0

From the 2026-10-01 comparison with Google's own tools and the community (docs/COMPETITION-2026-10-01.md).

Added

• serviceTier on ask and code (standard | flex), with the operator default GEMINI_CODE_CONTEXT_SERVICE_TIER
  (trimmed, case-insensitive; an invalid value warns on stderr and is standard): flex is Google's half-price tier
  (longer latency). The cost estimate, the usage ledger and the daily budget use the flex price. A request flex refuses
  under load (429/503) is NOT retried by this server — the network retry covers connection failures only; the result
  says RATE_LIMIT / OVERLOADED, retryable: true with Google's retry hint when it sent one (a 429/503 on the
  stale-cache retry is reported as itself), and the client retries; a flex request is sent exactly once — the server's
  own network retry is off for it, every send being billed. Reported as serviceTier on every result of a call that reached model resolution, errors and
  timeouts included (the requested tier until the model is resolved; the earliest validation errors — workspace,
  thinking budget — carry no tier); a failure before any response (a reset, the
  300 s header wait on a queued flex request) is NETWORK_ERROR, retryable: true; the ask_agentic fallback runs standard and says so (progress line, warning,
  serviceTierDowngraded). Not available on the Vertex AI backend (the SDK sends no tier there, js-genai#1468): a
  per-call flex is refused by name, a default of flex runs standard with a startup warning. Registered follow-ups:
  DEF-FLEX-01 (the fetch headers timeout on flex), DEF-FLEX-02 (the usage rows do not record the tier yet).