feat(orchestrator): slice 13d(i) — containerize the orchestrator (validated on docker)

Real-on-host testing surfaced two issues the unit-mocked slices couldn't:

1. The host (NixOS) firewall DROPS container->host traffic, so a host-process
   orchestrator is unreachable from the gateway container. Fix: run the
   orchestrator AS a container on the shared gateway network (PRD 0070's
   "virtualize the orchestrator") — the gateway reaches it by container name
   over docker DNS (container<->container, no firewall), and the host CLI
   reaches it via a published loopback port.
2. The control plane crashed the connection on a dispatch error (e.g. a
   broker failure) instead of returning 500.

Changes:
- lifecycle: OrchestratorProcess (host process) -> OrchestratorService
  (containers). Runs the control plane in the bundle image with the repo
  bind-mounted (orchestrator is stdlib-only), register-only stub broker so it
  needs NO docker socket (the backend launches agents; the host manages both
  containers). Registry DB persists via a host-root mount. ensure_running is
  an idempotent singleton over both containers.
- gateway: BOT_BOTTLE_ORCHESTRATOR_URL is now the orchestrator's *by-name*
  URL on the shared network (dropped the host.docker.internal hack).
- control_plane: _serve wraps dispatch — a failure returns 500, never crashes
  the connection.
- OrchestratorProcess default broker -> stub (register-only) for docker.

Validated live end-to-end: both containers up, gateway->orchestrator by name
OK, register -> resolve-by-source-IP returns the bottle's policy from inside
the gateway.

pyright 0 errors; pylint 9.83/10; unit suite green (1760 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

bot_bottle/orchestrator/__main__.py

@@ -51,7 +51,13 @@ def main(argv: list[str] | None = None) -> int:
     # anything; 'docker' runs real containers (firecracker drops in later).
     secret = secrets.token_bytes(32)
     broker: LaunchBroker = DockerBroker(secret) if args.broker == "docker" else StubBroker(secret)
-    gateway: Gateway | None = DockerGateway() if args.gateway else None
+    # Standalone `--gateway` (not the consolidated flow, where the host
+    # lifecycle runs the gateway). The gateway resolves against this same
+    # process; the URL is only reachable when they share a docker network.
+    gateway: Gateway | None = (
+        DockerGateway(orchestrator_url=f"http://{args.host}:{args.port}")
+        if args.gateway else None
+    )
     orchestrator = Orchestrator(registry, broker, secret, gateway)
 
     # One persistent per-host gateway, shared by every bottle: build the