Experimental line-delimited JSON runtime server for DeepCode clients.

The server owns lifecycle state and delegates model work to RuntimeHost. Completed items and terminal turn state are persisted; streaming deltas are notifications only. The initial transport is single-client stdio, matching the desktop packaging decision in docs/adr/0001-desktop-runtime-sidecar.md.

After a workspace build, run node apps/server/dist/cli.js and send one JSON request per line:

{ "id": 1, "method": "initialize", "params": {} }

The transport is experimental. Clients must negotiate protocolVersion before using it.