v0.2.81

Deduplicate requestless Claude content blocks whose OpenAI Responses resp_ ID repeats at different timestamps within the same session. Preserve separate sessions, distinct request IDs and reusable gateway placeholders. Parser cache fingerprints re-read retained logs after upgrading. Verified with official-source/schema-faithful regressions, 218 tests, typecheck, build and npm package validation. No new telemetry, permissions or upload fields.