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/backend/macos_container/util.py

@@ -445,12 +445,20 @@ def container_ipv4_on_network(name: str, network: str) -> str:
     return ip
 
 
-def run_container_argv(argv: list[str]) -> subprocess.CompletedProcess[str]:
+def run_container_argv(
+    argv: list[str], *, env: dict[str, str] | None = None,
+) -> subprocess.CompletedProcess[str]:
     """Run a `container` command, returning the result for the caller to
     interpret. Unlike the `die`-on-failure helpers above, this lets callers
     that raise their own typed errors (the gateway / orchestrator lifecycle)
-    keep control of the failure path."""
-    return subprocess.run(argv, capture_output=True, text=True, check=False)
+    keep control of the failure path.
+
+    `env` sets the child process environment — used to hand a secret to a bare
+    `--env NAME` flag (Apple's "just key → inherit from host" form) so the
+    value is inherited from this process, never written onto argv or into
+    `container inspect`'s recorded command line."""
+    return subprocess.run(
+        argv, capture_output=True, text=True, check=False, env=env)
 
 
 def bind_mount_spec(source: str, target: str, *, readonly: bool = False) -> str: