Moves chord2 (contracts, objects, cells, roots, plugins, hot reload, memory/IPC/WebSocket links)
from p2 into packages/chord, with its tests (now on vitest) and docs. The root export is the new
runtime plus the shared base (Context, JsonValue, JsonRepresentation, Draft, copyJson, isJsonValue,
replicatedState and its types). ./node now holds the host manager, child control, process locks,
and nodeLoader. ./context and ./delta are unchanged; ./bundler is removed.
replicatedState stays a standalone module with the same exports. It no longer exposes the exact-op
subscription the removed service provider used, so listener failures of mutable states are always
reported asynchronously. The package depends on typebox instead of esbuild. The wire format stays JSON.
