Replace the 'future strategies' section with the channel model:
- Channel 0 is the call protocol — the universal control plane. Handles
operation discovery (from_call), operation routing (invoke_peer),
service discovery, and channel negotiation (channel/open, channel/close,
channel/list).
- Channels 1..N carry any ALPN as data planes. Opened via channel/open on
the call protocol. Each channel is a bidirectional QUIC stream, wrapped
as Connection::from_bidi (ADR-065), and handed to the same
ProtocolHandler::handle() that handles dedicated connections. The
handler does not know it's on a multiplexed channel.
- Channel negotiation is symmetric — either side can open a channel.
Same pattern as from_call: bidirectional, symmetric, negotiated over
the call protocol.
- The hub's role for channels 1..N is transparent stream proxying. The
hub does not interpret the protocol; the client and worker speak the
ALPN directly.
- Hub struct gains channel tracking (PeerId → ChannelId → ChannelInfo).
HubError gains ChannelAlreadyOpen, ChannelNotFound, ChannelOpenFailed.
- New OQ-55: channel/open operation spec (deferred to call-protocol
implementation phase).