[hatoo]

A chunked HTTP/1 response must remain in flight until the empty line after its trailers is complete. Add native TCP and TLS worker tests that send 0-byte, 64 KiB and 1 MiB ignored trailer values, including binary lines, then withhold the final empty-line LF. The peer detects an early next request or connection close; the tests verify exact response/status counts, received socket bytes and every latency sample.

The independent Quinn replacement test used eight receive buffers, which can exhaust during a packet burst and produce an additional, correctly handled ENOBUFS completion. Size that fixture to the production worker's 64-buffer minimum while retaining its exact cancellation and generation assertions. A controlled 32-datagram replacement test now forces exhaustion with eight buffers and verifies rearming, all payloads, all buffer returns and exact accounting; the 64-buffer case must receive the same burst without a terminal completion. It observes retirement before injecting the burst so cancellation delivery order is explicit.

This PR changes regression fixtures only.

Validation:

• cargo test --locked and cargo test --release --locked: 511 unit and 62 integration tests pass per profile; two existing tests remain ignored.
• cargo clippy --locked --all-targets -- -D warnings and cargo fmt --check: pass.
• All six HTTP/3 lifetime tests pass, including controlled exhaustion and the independent Quinn response.
• An intentionally broken parser that completes at the zero-sized chunk fails both new HTTP/1 tests with response completed before final LF; the default parser was restored before the full passing checks.