Http3

Dependencies and toolchain

• Updated quiche to 0.29.1 and refreshed the compatible Rust dependency graph, including the jemalloc wrapper stack.
• Raised the Rust minimum version to 1.96.
• Updated the Docker build, test, runtime test, and verification image toolchains to Rust 1.96.0.

HTTP/3 stream lifecycle

• Used quiche's closed-stream signal to prune H3 stream bookkeeping after finished/reset streams, preventing stale drain and trailer-FIN state from surviving terminal stream cleanup.
• Dropped queued H3 pending writes and pending responses when quiche reports the stream closed, releasing outbound admission instead of retrying work that can no longer flush.
• Added a direct quiche/H3 regression covering closed-stream cleanup after a headers-only response.

Formal verification

• Added a pure stream-tracking model for H3 and worker per-stream cleanup state.
• Added Kani harnesses proving closed-stream cleanup removes all target stream state, preserves unrelated streams, and is idempotent, while non-closed cleanup is a no-op.

Release metadata

• Bumped the package line to 0.8.5, including Cargo metadata, native sidecar package manifests, and root optional sidecar pins.