test(bridge): cover synthesized Host on raw HTTP/1.1 wire

[fannnzhang]

Summary

• Add a raw HTTP/1.1 regression test that fails with 400 when the wire request lacks Host.
• Assert the direct HTTP/1.1 send path keeps origin-form request targets while preserving the bridge-synthesized Host header.

Notes

• v0.1.0 already injects Host in BridgeInterceptor::normalize_host_header.
• Current main further canonicalizes synthesized host values by omitting default :80 / :443 ports.
• This change adds end-to-end raw-wire coverage for the openresty-style missing-Host failure mode.

Verification

• cargo fmt --all --check
• cargo test -p openwire --lib bridge::tests -- --nocapture
• cargo test -p openwire bridge_interceptor_sends_synthesized_host_on_raw_http11_wire --test integration -- --nocapture
• cargo test -p openwire bridge_interceptor --test integration -- --nocapture