Re-sync core/protocol/* from upstream (they were verbatim copies), re-fork
core/box.go onto the new upstream box.go, and adapt to changed APIs:
- adapter.ConnectionTracker gained RoutedFlow; add no-op impls to both trackers
- log.ObservableFactory gained AttachPlatformWriter; add no-op impl
- box.Context now takes a CertificateProviderRegistry; wire one up with
the origin_ca provider
- box.go now depends on debug*.go; copy them from upstream
- hysteria inbound moved QUIC option building into quic.go; copy it
Deps: sing v0.9.0-beta.4, sing-quic v0.7.0-beta.4, sing-tun v0.9.0-beta.2.
Runtime behaviour is not yet validated and config migration for options
deprecated in 1.14 is not done, so this is not ready for main.
