fix(security): authenticate the orchestrator control plane (issue #400 Critical)

The control plane had no caller authentication — dispatch() routed every
request straight through, and the only guards anywhere were the
(source_ip, identity_token) checks inside /resolve and /attribute, which
authenticate the *bottle* a request is about, not the *caller*. On the
consolidated backends the agent shares a network with the control-plane port
(macOS: the infra container runs 8099 on the agent's --internal network;
docker: the orchestrator container sits on the shared gateway network), so a
prompt-injected agent could GET /bottles (enumerate siblings + policies),
PUT /bottles/<id>/policy (rewrite its own egress allowlist to allow-all),
POST /resolve (read the injected upstream credentials it's never meant to
see), and POST /supervise/respond (self-approve its own proposals). Every
README guarantee collapsed to the agent's discretion.

Fix: a per-host control-plane secret required on every route but GET /health,
compared with hmac.compare_digest. It is held only by the trusted callers and
never handed to an agent:
- minted + persisted 0600 at <root>/control-plane-token (paths.host_control_plane_token);
- injected as $BOT_BOTTLE_CONTROL_PLANE_TOKEN into the orchestrator + gateway
  containers via bare `--env NAME` (value inherited from the launch process,
  so it never lands on argv or in `container/docker inspect`);
- presented by the gateway's PolicyResolver (reads the env) on /resolve, and by
  the host CLI's OrchestratorClient (reads the host file) on every call.

The agent container is never given the env var or the host file, so from a
bottle every /bottles*, /resolve, /attribute, and /supervise/* call now
returns 401 — closing the enumeration, allowlist-rewrite, credential-lift, and
self-approval. The existing (source_ip, identity_token) checks stay as
defense-in-depth.

Enforced when configured: macOS + docker inject the secret (→ enforced). With
no secret set the server runs open and warns loudly at startup — a
fail-visible fallback for the unit suite and for Firecracker, whose
port-scoped nft already blocks agents from 8099 (wiring the secret into its
infra-VM init is a clean fast-follow, left out here to avoid churning the
prebuilt-artifact hash).

Verified end-to-end on real Apple Container: infra comes up healthy, the host
CLI (with the secret) lists bottles while an unauthenticated GET /bottles gets
401, all five issue-#400 attacks from inside the agent get 401, and egress
policy still works (200 allowed / 403 denied) — proving the gateway
authenticates to /resolve with the secret. 1829 unit tests pass, pyright
clean, pylint 9.91.

Refs #400.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

bot_bottle/orchestrator/gateway.py

@@ -23,7 +23,11 @@ import time
 from pathlib import Path
 
 from ..docker_cmd import run_docker
-from ..paths import host_db_path
+from ..paths import (
+    CONTROL_PLANE_TOKEN_ENV,
+    host_control_plane_token,
+    host_db_path,
+)
 from ..supervise import DB_PATH_IN_CONTAINER
 
 # The host DB dir is bind-mounted here so the gateway's supervise daemon
@@ -215,12 +219,19 @@ class DockerGateway(Gateway):
         ]
         for port in self._host_port_bindings:
             argv += ["--publish", f"0.0.0.0:{port}:{port}"]
+        run_env = dict(os.environ)
         if self._orchestrator_url:
             # Makes the gateway's egress / git / supervise daemons multi-tenant:
             # each request resolves source-IP -> policy against the control plane.
             argv += ["--env", f"BOT_BOTTLE_ORCHESTRATOR_URL={self._orchestrator_url}"]
+            # ...and presents the control-plane secret on those /resolve calls
+            # (the control plane requires it). Bare `--env NAME` keeps the value
+            # off argv / `docker inspect`; only the gateway (not the agent) is
+            # given it. Only needed in multi-tenant mode, where /resolve is used.
+            argv += ["--env", CONTROL_PLANE_TOKEN_ENV]
+            run_env[CONTROL_PLANE_TOKEN_ENV] = host_control_plane_token()
         argv.append(self.image_ref)
-        proc = run_docker(argv)
+        proc = run_docker(argv, env=run_env)
         if proc.returncode != 0:
             raise GatewayError(f"gateway failed to start: {proc.stderr.strip()}")