Extract the auth + directory-header encoding from sdk.ts into a pure, dep-free
headers.ts (sdk.ts now delegates — behavior unchanged) so the connection-critical
logic is unit-testable without expo/fetch. Add 8 header tests (ASCII passthrough,
non-ASCII/CJK percent-encoding stays header-safe, Basic auth, empty-dir handling)
and 8 logbuffer tests (serialization incl. circular-ref fallback, 200-entry ring
cap, copy semantics, formatting). typecheck clean.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
