v2.6.0 - Request lifecycle and verification

v2.6.0 - Request lifecycle and verification

• Added a reusable fake Steam transport, independent outgoing/incoming wire fixtures,
  and a shared randomized inspect corpus. New tests are no longer hidden by the test-directory ignore rule.
• Centralized request cleanup and same-key serialization; added cancelPendingRequests(),
  dispose(), and RequestError codes with mutation uncertainty. Failed sent keys remain
  quarantined for the client lifetime and are never automatically retried.
• Fixed subscription-after-send races, wrong notification correlation, discarded additional
  profiles, absent wear coerced to zero, duplicate/reordered inventory changes, unsigned
  storage-unit IDs, and malformed nested protobuf/craft payload handling.
• Added schema-generated public response/event types and compile-time consumer examples.
  Corrected Promise overload inference and the numeric ItemInfo.accountid declaration.
• Added an explicit feature support matrix and a safe, opt-in
  authenticated live runner with individually designated mutations and inventory assertions.
• Added packed consumer CI across Node 14/16/18/20/22/24 and steam-user 4.2.0/4.29.3/5.3.0.

Migration: existing calls remain compatible. Handle request rejections, reconcile uncertain
mutations before any manual retry, and dispose unused clients. Read FEATURE_SUPPORT.md
for quarantine semantics and callback differences. Live Steam/GC behavior remains unverified;
schema-correct sends and offline notifications do not establish server-side feature support.

Validation: 162 offline tests; lint and strict declaration checks; packed artifacts tested with steam-user 4.2.0, 4.29.3 and 5.3.0 across Node 14/16/18/20/22/24 in CI and Node 26.10.0 locally. PR: #13. Live behavior remains unverified.