Remove the supervise flag; supervise every bottle

Issue #249: in practice the per-bottle `supervise` flag was never
turned off — all bottles should be supervised. Remove the manifest
flag and make the supervise sidecar unconditional, mirroring egress.

- Reject `supervise:` as a removed bottle key with a migration hint.
- Drop the `supervise` field from ManifestBottle and the extends merge.
- prepare_supervise always returns a SupervisePlan; the plan type is
  now non-optional and the per-backend `is None` guards are gone, so
  the supervise daemon, current-config mount, aliases, and MCP
  registration always render.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01YcU7nerbg8cVj9R4EkpfLJ

bot_bottle/backend/smolmachines/launch.py

@@ -206,12 +206,10 @@ def _discover_urls(
         )
         agent_git_gate_host = f"{loopback_ip}:{git_gate_host_port}"
 
-    agent_supervise_url = ""
-    if plan.supervise_plan is not None:
-        supervise_host_port = _bundle.bundle_host_port(
-            plan.slug, _SUPERVISE_PORT, host_ip=loopback_ip,
-        )
-        agent_supervise_url = f"http://{loopback_ip}:{supervise_host_port}/"
+    supervise_host_port = _bundle.bundle_host_port(
+        plan.slug, _SUPERVISE_PORT, host_ip=loopback_ip,
+    )
+    agent_supervise_url = f"http://{loopback_ip}:{supervise_host_port}/"
 
     existing_no_proxy = plan.guest_env.get("NO_PROXY", "localhost,127.0.0.1")
     no_proxy = f"{existing_no_proxy},{loopback_ip}"
@@ -299,15 +297,14 @@ def _bundle_launch_spec(
     """Build a BundleLaunchSpec from the resolved inner Plans.
 
     Daemons in the CSV:
-      - egress is always present.
+      - egress and supervise are always present.
       - git-gate + git-http are conditional on plan.git_gate_plan.upstreams.
-      - supervise is conditional on plan.supervise_plan.
 
     Env + volumes are the union of the sidecar daemons' needs, with
     daemon-private values only (HTTPS_PROXY is scoped to the
     egress process by egress_entrypoint.sh — see PRD 0024's bundle
     bind-address PR)."""
-    daemons: list[str] = ["egress"]
+    daemons: list[str] = ["egress", "supervise"]
     env: list[str] = []
     volumes: list[tuple[str, str, bool]] = []
 
@@ -347,23 +344,19 @@ def _bundle_launch_spec(
 
     # --- supervise --------------------------------------------
     sp = plan.supervise_plan
-    if sp is not None:
-        daemons.append("supervise")
-        env += [
-            f"SUPERVISE_BOTTLE_SLUG={plan.slug}",
-            f"SUPERVISE_QUEUE_DIR={QUEUE_DIR_IN_CONTAINER}",
-            f"SUPERVISE_PORT={SUPERVISE_PORT}",
-        ]
-        volumes.append((str(sp.queue_dir), QUEUE_DIR_IN_CONTAINER, False))
+    env += [
+        f"SUPERVISE_BOTTLE_SLUG={plan.slug}",
+        f"SUPERVISE_QUEUE_DIR={QUEUE_DIR_IN_CONTAINER}",
+        f"SUPERVISE_PORT={SUPERVISE_PORT}",
+    ]
+    volumes.append((str(sp.queue_dir), QUEUE_DIR_IN_CONTAINER, False))
 
     # Container ports the agent reaches from the smolvm guest —
     # published on host loopback so the guest can dial via TSI +
     # macOS networking. Egress is always the agent's HTTP/HTTPS proxy.
-    ports_to_publish: list[int] = [_EGRESS_PORT]
+    ports_to_publish: list[int] = [_EGRESS_PORT, _SUPERVISE_PORT]
     if gp.upstreams:
         ports_to_publish.append(_GIT_HTTP_PORT)
-    if sp is not None:
-        ports_to_publish.append(_SUPERVISE_PORT)
 
     return _bundle.BundleLaunchSpec(
         slug=plan.slug,