v0.8.4

What's Changed

• fix(tunnel): restore small-batch inline fast path (regression fix) by @btdt1983 in #18
• fix(tunnel): fix outbound seal ordering race (correctness bug) by @btdt1983 in #19
• fix(tunnel): raise INLINE_THRESHOLD to the proven 128 value by @btdt1983 in #20
• refactor(engine): reserve-then-parallel-seal crypto pipeline, wireguard-go style by @btdt1983 in #21

Full Changelog: v0.8.3...v0.8.4