feat(docker): per-profile s6 supervision + container-restart reconciliation

Phase 4 of the s6-overlay supervision plan. Activates the Phase 3
S6ServiceManager by hooking it into the profile lifecycle and the
`hermes gateway start/stop/restart` dispatcher, and adds a cont-
init.d-time reconciliation pass that survives `docker restart`.

Task 4.0 — container-boot reconciliation:
  /run/service/ is tmpfs, so every `docker restart` wipes every
  per-profile gateway slot. /etc/cont-init.d/02-reconcile-profiles
  invokes hermes_cli.container_boot.reconcile_profile_gateways() on
  every boot, which walks $HERMES_HOME/profiles/<name>/, reads each
  gateway_state.json, recreates the s6 service slot, and auto-starts
  only those whose last state was 'running'. Other states
  (stopped, starting, startup_failed, missing) register the slot
  in the down state — avoiding crash-loops across restarts for a
  gateway that was broken last boot. Per-profile outcome is recorded
  to $HERMES_HOME/logs/container-boot.log.

  Implementation: hermes_cli/container_boot.py + 12 unit tests.
  Profile-marker is SOUL.md, not config.yaml, because `hermes profile
  create` only seeds SOUL.md by default (config.yaml comes from
  `hermes setup`).

Task 4.1 / 4.2 — profile create/delete hooks:
  hermes_cli/profiles.py::create_profile now calls
  _maybe_register_gateway_service(<canon>) at the end, which routes
  through ServiceManager.register_profile_gateway when running on s6
  and no-ops on host backends. delete_profile mirrors with
  _maybe_unregister_gateway_service. _allocate_gateway_port produces
  a deterministic SHA-256-derived port in [9200, 9800).

Task 4.3 — gateway dispatch + remove rejection arms:
  _dispatch_via_service_manager_if_s6(action) intercepts
  start/stop/restart at the top of each subcommand and routes them
  through S6ServiceManager.{start,stop,restart}. The pre-Phase-4
  `elif is_container():` rejection arms are kept as fallback for
  pre-s6 containers / unsupported runtimes, but only ever fire when
  detect_service_manager() != 's6'. install/uninstall under s6
  print informational guidance pointing users at profile create/delete.

  Removed the two xfail(strict=True) markers from
  tests/docker/test_profile_gateway.py — both tests now pass strictly.

Task 4.4 — status reporting:
  get_gateway_runtime_snapshot() reports
  Manager: 's6 (container supervisor)' inside an s6 container instead
  of 'docker (foreground)'.

Plan-vs-reality drift fixed in this commit:
  - Plan's S6ServiceManager._render_run_script used
    `gateway start --foreground --port {port}` — invented args; the
    real CLI is `gateway run`. Switched accordingly. port arg
    retained for API parity but now documented as 'currently ignored'.
  - Plan's reconciler keyed on config.yaml; switched to SOUL.md
    (config.yaml is created by hermes setup, not by hermes profile
    create, so the original gate caught nothing).
  - The plan's _dispatch helper used _profile_arg() which returns
    '--profile <name>' (i.e. with the flag prefix). Switched to
    _profile_suffix() which returns the bare name.
  - Architecture B's docker exec doesn't get /command on PATH or
    the venv on PATH; Dockerfile's runtime PATH now includes
    /opt/hermes/.venv/bin so 'docker exec <c> hermes ...' works
    without sourcing the venv.
  - stage2-hook now chowns $HERMES_HOME/profiles to hermes on every
    boot, not just on the UID-remap path. Without this, files created
    by docker-exec-as-root accumulate and the next reconciler run
    fails with PermissionError reading SOUL.md.

Test harness:
  19 passed, 0 xfailed (the two pre-Phase-4 xfail targets flip to
  passing). 78 unit tests across service_manager + container_boot +
  profiles_s6_hooks + gateway_s6_dispatch. Hadolint + shellcheck
  pass cleanly.

Refs: docs/plans/2026-05-07-s6-overlay-dynamic-subagent-gateways.md

Dockerfile

@@ -138,18 +138,29 @@ RUN uv pip install --no-cache-dir --no-deps -e "."
 COPY docker/s6-rc.d/ /etc/s6-overlay/s6-rc.d/
 
 # stage2-hook handles UID/GID remap, volume chown, config seeding,
-# skills sync, and TUI detection — all the work the old entrypoint.sh
-# did between gosu-drop and `exec hermes`. Wired in as cont-init.d/01-
-# so it runs before any user services start.
+# skills sync — all the work the old entrypoint.sh did between
+# gosu-drop and `exec hermes`. Wired in as cont-init.d/01- so it
+# runs before user services start.
+#
+# 02-reconcile-profiles re-creates per-profile gateway s6 service
+# slots from $HERMES_HOME/profiles/<name>/ after a container restart
+# (the /run/service/ scandir is tmpfs and wiped on restart). Phase 4.
 RUN mkdir -p /etc/cont-init.d && \
     printf '#!/bin/sh\nexec /opt/hermes/docker/stage2-hook.sh\n' \
         > /etc/cont-init.d/01-hermes-setup && \
     chmod +x /etc/cont-init.d/01-hermes-setup
+COPY --chmod=0755 docker/cont-init.d/02-reconcile-profiles /etc/cont-init.d/02-reconcile-profiles
 
 # ---------- Runtime ----------
 ENV HERMES_WEB_DIST=/opt/hermes/hermes_cli/web_dist
 ENV HERMES_HOME=/opt/data
-ENV PATH="/opt/data/.local/bin:${PATH}"
+# Pre-s6 entrypoint.sh did `source .venv/bin/activate` which exported
+# the venv bin onto PATH; Architecture B's main-wrapper.sh does the
+# same for the container's main process, but `docker exec` and our
+# cont-init.d scripts don't pass through the wrapper. Expose the venv
+# bin globally so `docker exec <container> hermes ...` and any
+# subprocess that doesn't activate the venv first still find hermes.
+ENV PATH="/opt/hermes/.venv/bin:/opt/data/.local/bin:${PATH}"
 RUN mkdir -p /opt/data
 VOLUME [ "/opt/data" ]