refactor(orchestrator): rename Sidecar -> Gateway for the consolidated data plane

Retire "sidecar" for the consolidated per-host path (PRD 0070 naming
decision): the orchestrator is the umbrella/control plane, and the
egress/git/supervise data-plane unit it runs is the "gateway".

- git mv sidecar.py -> gateway.py and the two integration + one unit test
  files; DockerSidecar->DockerGateway, Sidecar->Gateway,
  SidecarError->GatewayError, SIDECAR_*->GATEWAY_*, ensure_sidecar->
  ensure_gateway, sidecar_status->gateway_status, container name
  bot-bottle-orch-sidecar->bot-bottle-orch-gateway.
- Prose rename across broker/registry/egress/policy_resolver + PRD 0070.
- Preserved: the image name bot-bottle-sidecars, the
  BOT_BOTTLE_SIDECAR_IMAGE env var, Dockerfile.sidecars, and PRD 0069's
  own stage-name cross-references (that doc still uses "sidecar").

No behavior change. Full unit suite green (1679 tests; the 13
test_sidecar_init /bin/sleep errors are pre-existing NixOS-local noise).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WBMWTEtQdJ4W5UrWuLHCck

tests/unit/test_orchestrator_gateway.py

@@ -0,0 +1,129 @@
+"""Unit tests for the consolidated Docker gateway (PRD 0070). Docker mocked."""
+
+from __future__ import annotations
+
+import unittest
+from unittest.mock import Mock, patch
+
+from bot_bottle.orchestrator.gateway import (
+    GATEWAY_NAME,
+    DockerGateway,
+    GatewayError,
+)
+
+_RUN_DOCKER = "bot_bottle.orchestrator.gateway.run_docker"
+
+
+def _proc(returncode: int = 0, stdout: str = "", stderr: str = "") -> Mock:
+    return Mock(returncode=returncode, stdout=stdout, stderr=stderr)
+
+
+class TestDockerGateway(unittest.TestCase):
+    def setUp(self) -> None:
+        self.sc = DockerGateway("bot-bottle-sidecars:latest")
+
+    def test_default_name(self) -> None:
+        self.assertEqual(GATEWAY_NAME, self.sc.name)
+
+    def test_is_running_reads_docker_ps(self) -> None:
+        with patch(_RUN_DOCKER, return_value=_proc(stdout=self.sc.name + "\n")):
+            self.assertTrue(self.sc.is_running())
+        with patch(_RUN_DOCKER, return_value=_proc(stdout="")):
+            self.assertFalse(self.sc.is_running())
+
+    def test_ensure_running_is_noop_when_already_up(self) -> None:
+        with patch(_RUN_DOCKER, return_value=_proc(stdout=self.sc.name)) as m:
+            self.sc.ensure_running()
+        # Only the is_running() ps probe — no rm / run.
+        self.assertEqual(1, m.call_count)
+
+    def test_ensure_running_starts_the_singleton_when_absent(self) -> None:
+        calls: list[list[str]] = []
+
+        def fake(argv: list[str]) -> Mock:
+            calls.append(argv)
+            return _proc(stdout="") if argv[:2] == ["docker", "ps"] else _proc()
+
+        with patch(_RUN_DOCKER, side_effect=fake):
+            self.sc.ensure_running()
+
+        runs = [c for c in calls if c[:2] == ["docker", "run"]]
+        self.assertEqual(1, len(runs))
+        self.assertIn(self.sc.name, runs[0])
+        self.assertIn("bot-bottle-sidecars:latest", runs[0])
+
+    def test_ensure_running_raises_on_docker_failure(self) -> None:
+        def fake(argv: list[str]) -> Mock:
+            if argv[:2] == ["docker", "ps"]:
+                return _proc(stdout="")
+            if argv[:2] == ["docker", "run"]:
+                return _proc(returncode=1, stderr="boom")
+            return _proc()
+
+        with patch(_RUN_DOCKER, side_effect=fake):
+            with self.assertRaises(GatewayError):
+                self.sc.ensure_running()
+
+    def test_stop_is_idempotent_on_missing(self) -> None:
+        absent = _proc(returncode=1, stderr="Error: No such container: x")
+        with patch(_RUN_DOCKER, return_value=absent):
+            self.sc.stop()  # must not raise
+
+    def test_stop_raises_on_other_failure(self) -> None:
+        with patch(_RUN_DOCKER, return_value=_proc(returncode=1, stderr="daemon down")):
+            with self.assertRaises(GatewayError):
+                self.sc.stop()
+
+
+class TestDockerGatewayBuild(unittest.TestCase):
+    def setUp(self) -> None:
+        self.sc = DockerGateway()  # defaults to the real bundle image + dockerfile
+
+    def test_image_exists_reads_docker_inspect(self) -> None:
+        with patch(_RUN_DOCKER, return_value=_proc(returncode=0)):
+            self.assertTrue(self.sc.image_exists())
+        with patch(_RUN_DOCKER, return_value=_proc(returncode=1)):
+            self.assertFalse(self.sc.image_exists())
+
+    def test_ensure_built_is_noop_when_image_present(self) -> None:
+        with patch(_RUN_DOCKER, return_value=_proc(returncode=0)) as m:
+            self.sc.ensure_built()
+        self.assertEqual(1, m.call_count)  # only the image-inspect probe
+
+    def test_ensure_built_builds_from_dockerfile_when_missing(self) -> None:
+        calls: list[list[str]] = []
+
+        def fake(argv: list[str]) -> Mock:
+            calls.append(argv)
+            if argv[:3] == ["docker", "image", "inspect"]:
+                return _proc(returncode=1)  # missing
+            return _proc()
+
+        with patch(_RUN_DOCKER, side_effect=fake):
+            self.sc.ensure_built()
+
+        builds = [c for c in calls if c[:2] == ["docker", "build"]]
+        self.assertEqual(1, len(builds))
+        self.assertIn(self.sc.image_ref, builds[0])
+        self.assertIn("-f", builds[0])
+        self.assertTrue(any(a.endswith("Dockerfile.sidecars") for a in builds[0]))
+
+    def test_ensure_built_noop_when_no_dockerfile(self) -> None:
+        sc = DockerGateway("busybox", dockerfile=None)
+        with patch(_RUN_DOCKER) as m:
+            sc.ensure_built()
+        m.assert_not_called()
+
+    def test_ensure_built_raises_on_build_failure(self) -> None:
+        def fake(argv: list[str]) -> Mock:
+            if argv[:3] == ["docker", "image", "inspect"]:
+                return _proc(returncode=1)
+            return _proc(returncode=1, stderr="build boom")
+
+        with patch(_RUN_DOCKER, side_effect=fake):
+            with self.assertRaises(GatewayError):
+                self.sc.ensure_built()
+
+
+if __name__ == "__main__":
+    unittest.main()