refactor(de-sidecar): remove the per-bottle companion-container architecture

The per-agent companion container (the egress/git-gate/supervise data
plane run once per bottle) is the pre-consolidation architecture. Remove
it and disable the backends that still depend on it, per the #385 thread.

- Delete `backend/docker/sidecar_bundle.py`; docker's live path uses the
  consolidated shared gateway, not a per-bottle bundle.
- Disable the firecracker and macos-container backends: their `launch()`
  fails closed (they launched a per-bottle companion; firecracker's
  consolidated relaunch is #354, macos follows). Their `enumerate` return
  empty and `cleanup` drop the companion-container discovery (firecracker
  keeps VMM/run-dir cleanup).
- Fail-close both backends' `egress_apply` reload (it signalled the
  per-bottle container); consolidated egress policy resolves per-request
  against the orchestrator, so gateway-side apply is a follow-up.
- Rename `egress_sidecar_env_entries` → `egress_gateway_env_entries`,
  `SIDECAR_PORTS` → `GATEWAY_PORTS`.
- Move the shared DockerBottlePlan fixture to `tests/unit/_docker_bottle_plan.py`;
  delete tests for the removed launch paths; update cleanup/egress-apply tests.

Docker consolidated launch verified end-to-end (multitenant isolation
integration test passes). macos/firecracker are intentionally disabled.

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

tests/unit/test_egress_apply.py

@@ -70,32 +70,16 @@ class TestApplyRoutesChange(unittest.TestCase):
         self.addCleanup(self._tmp.cleanup)
         self.addCleanup(use_bottle_root(Path(self._tmp.name) / ".bot-bottle"))
 
-    def test_writes_live_routes_and_signals_reload(self):
-        calls: list[list[str]] = []
-
-        def fake_run(argv: list[str], **kwargs: object) -> SimpleNamespace:
-            calls.append(list(argv))
-            return SimpleNamespace(returncode=0, stdout="", stderr="")
-
-        with patch(
-            "bot_bottle.backend.docker.egress_apply.subprocess.run",
-            side_effect=fake_run,
-        ):
-            before, after = applicator.apply_routes_change(
+    def test_apply_routes_change_fails_closed_after_companion_removal(self):
+        # The per-bottle companion container that live route-apply used to
+        # signal was removed in the de-sidecar cleanup (#385); apply now
+        # fails closed until the gateway-side apply lands.
+        with self.assertRaises(EgressApplyError) as cm:
+            applicator.apply_routes_change(
                 "dev",
                 "routes:\n  - host: google.com\n",
             )
-
-        self.assertEqual("", before)
-        self.assertEqual("routes:\n  - host: google.com\n", after)
-        self.assertEqual(
-            "routes:\n  - host: google.com\n",
-            (Path(self._tmp.name) / ".bot-bottle/state/dev/egress/routes.yaml").read_text(encoding="utf-8"),
-        )
-        self.assertEqual(
-            ["docker", "kill", "--signal", "HUP", "bot-bottle-sidecars-dev"],
-            calls[0],
-        )
+        self.assertIn("consolidated gateway", str(cm.exception))
 
 
 if __name__ == "__main__":