feat(docker): split orchestrator and gateway into separate containers (PRD 0070)

Now that #469 got the DB off the data plane, the docker backend runs the
control plane and data plane as two containers instead of the combined
`bot-bottle-infra` container:

  * bot-bottle-orchestrator — the lean control-plane container (image
    Dockerfile.orchestrator, `-m bot_bottle.orchestrator`). Joins the new
    `bot-bottle-orchestrator` control network (`--internal`) only, plus a
    host-loopback publish for the CLI. Sole opener of bot-bottle.db; holds the
    signing key; no CA, no gateway daemons.
  * bot-bottle-orch-gateway — the data-plane container (DockerGateway),
    dual-homed on the agent `bot-bottle-gateway` network AND the control
    network, so it resolves the orchestrator by name
    (http://bot-bottle-orchestrator:8099) while agents — never on the control
    network — have no route to the control plane (the L3 block, not just the
    JWT). Holds the gateway JWT + the mitmproxy CA.

DockerInfraService now orchestrates the pair (builds gateway + orchestrator
images, brings up the orchestrator then the gateway) and exposes gateway_name;
the launch flow attributes agents against the gateway container. DockerGateway
gains a control_network it joins after run. rotate_ca / the CA read target the
gateway container. The combined Dockerfile.infra is no longer built by docker
(firecracker/macOS still use it until their splits).

pyright 0 errors; unit suite green (2273). Integration tests updated for the
two-container shape but need a real-docker run to validate the networking.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tests/unit/test_backend_secret_reprovision.py

@@ -82,8 +82,10 @@ class TestMacosReprovision(unittest.TestCase):
 
 class TestDockerReprovision(unittest.TestCase):
     def test_maps_network_containers_to_keys(self) -> None:
+        # The gateway container (excluded — it's on the data network but isn't
+        # an agent) + one agent + a malformed line.
         inspect = _proc(stdout=(
-            "bot-bottle-infra 172.18.0.2/16\n"
+            "bot-bottle-orch-gateway 172.18.0.2/16\n"
             "bot-bottle-a 172.18.0.3/16\n"
             "malformed\n"
         ))