Add an explicit Streamable HTTP entry for environment/gateway hosts while keeping stdio registrations and default behavior. Preserve the shared provider/session owner across DELETE and replacement; fence and drain tool/completion work before handover or teardown.
Bound HTTP input and plain-response admission, cancel refused bodies, join whole exchanges and asynchronous response cleanup before provider hooks, gate startup readiness, and reject queued HTTP/1.1 pipelining while retaining sequential keep-alive.
Validation: 8 static/build tasks, 83 adapter tests and registry metadata pass. A real installed gh binary produces seven equivalent CLI/stdio/HTTP reports with DELETE/replacement and clean signal shutdown. Broader local native-provider/ownership failures reproduce on clean main and are documented with limitations in the PR.
Co-authored-by: Edgar Arakelyan <edgar.arakelyan@scale.com>
Co-authored-by: gensokyo-dev <342580529+gensokyo-dev@users.noreply.github.com>
