v1.47.0

Opt-in: one shared Codex host for a flow walk. A Codex worker starts its
own codex exec process: the launcher, the native binary, a login-shell
snapshot and git probes. Native Codex runs its subagents as threads in one
process. Codex lab R200 measured about 114 s from codex exec launch to the
first model turn for each cold builder, because the lab guards every process.
R202 measured 0.05 s from a native subagent spawn to its own turn.

• Set "defaults": {"codex_host": true} in the graph, or
  PUPPETMASTER_CODEX_HOST=1 for the walker. A graph value wins. Off by
  default.
• The top walker starts one codex app-server on a Unix socket
  (codex_host.py) and stops it at walk end. Child walkers and workers find
  it through PUPPETMASTER_CODEX_HOST_RECORD. The next walk of the run stops
  a host that a dead walker left.
• Each Codex agent and judge runs as a thread on the host
  (codex_session.run_host_turn, stdlib WebSocket client codex_ws.py). A
  repair resumes its thread. A cut interrupts only its own turn. An approval
  request is declined and fails the turn.
• The adapter reports file changes and commands as codex exec --json
  items, so the write-scope gate, rollout usage and resume do not change.
  Each worker gets its own shell environment through the thread's
  shell_environment_policy.
• These runs use codex exec: a fork, a bypass run, a native-steer run, a
  custom executable, extra arguments other than -c key=value, a thread in
  another Codex home, and Windows (no Unix sockets). A host that does not
  start, or a connection that fails before the turn, also falls back.
• Each host turn writes codex_host_turn.json: host start and ready times,
  the request time, the thread start and the turn start.
• Replica (R179 regions graph, Sol 6.1 high, 3 interleaved pairs): host on
  548.6 / 292.2 / 370.6 s, host off 345.4 / 600.4 / 372.8 s. All runs
  passed the judge. Host runs: 69 of 69 turns on the host, 0 codex exec
  dispatches, request to own-turn start median 1.13 s. A local codex exec
  start is about 1.7 s, so the wall time does not change on this Mac.