feat(smolmachines): rewrite Smolfile to smolvm 0.8.0 schema + drop gvproxy (PRD 0023 chunk 2a)

First sub-PR of chunk 2: rewrite the renderer chunk 1 shipped to
match smolvm 0.8.0's actual Smolfile shape, delete the dead
gvproxy renderer + its tests, simplify the prepare flow now that
there's no gvproxy socket + no loopback-port allocation.

Smolfile renderer:
- Old shape (under the abandoned gvproxy design): name = ...,
  command = [...], [[net]] attachment = "unixgram",
  socket = "...".
- New shape (smolvm 0.8.0): env = [...] (sorted K=V pairs),
  [network] allow_cidrs = ["<bundle-ip>/32"]. Nothing else.
  image / entrypoint / cmd come from the .smolmachine artifact
  built in chunk 2b; cpus / memory left at smolvm defaults.
- Tests assert no leakage of TSI's --outbound-localhost-only or
  the old gvproxy/unixgram keys.

util.py:
- smolmachines_gvproxy_subnet → smolmachines_bundle_subnet,
  returning (subnet, gateway, bundle_ip). bundle_ip is always
  at .2 (gateway .1); subnet is /24, third octet derived from
  the slug hash, skipping the docker-default 17 to avoid the
  common 192.168.17.x collision.
- allocate_loopback_port: deleted. The bundle gets a pinned
  docker IP now; the agent dials that IP directly through TSI.
- smolmachines_preflight: dropped the gvproxy check; only
  smolvm is required.

prepare.py:
- Drops the gvproxy.yaml render + the loopback port allocation
  + the gvproxy_socket field on the plan.
- Derives subnet / gateway / bundle_ip from the slug and
  populates the new SmolmachinesBottlePlan fields.
- Agent env now uses IP-literal URLs (http://<bundle-ip>:8888
  etc) since the guest will have no DNS resolver inside TSI's
  allowlist.

bottle_plan.py:
- Old fields: gvproxy_config_path, gvproxy_socket,
  gvproxy_subnet, gvproxy_gateway, host_port_map.
- New fields: bundle_subnet, bundle_gateway, bundle_ip,
  smolfile_path. (smolmachine artifact path lands in chunk 2b.)

Net: -410 lines. Full unit suite: 516 passing.

The VM lifecycle + bundle bringup + launch wiring + smoke tests
land in chunk 2b.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

claude_bottle/backend/smolmachines/bottle_plan.py

@@ -1,10 +1,10 @@
 """SmolmachinesBottlePlan — concrete BottlePlan for the smolmachines
 backend (PRD 0023).
 
-Chunk 1 fields: slug, smolfile_path, gvproxy_config_path, gvproxy
-subnet + socket, and the per-bottle port map. VM lifecycle fields
-(machine name, OCI archive path, etc.) land in later chunks as the
-launch flow grows."""
+Chunk 1 + 2a fields: slug, smolfile_path, bundle docker subnet /
+gateway / pinned IP. VM lifecycle + provisioning fields (machine
+name, `.smolmachine` artifact path, etc.) land in later chunks
+as the launch flow grows."""
 
 from __future__ import annotations
 
@@ -25,14 +25,12 @@ class SmolmachinesBottlePlan(BottlePlan):
 
     slug: str
     smolfile_path: Path
-    gvproxy_config_path: Path
-    gvproxy_socket: Path
-    gvproxy_subnet: str
-    gvproxy_gateway: str
-    # Daemon name → host-side loopback port the bundle binds.
-    # Always includes "pipelock"; "git-gate" and "supervise"
-    # conditional on the bottle's manifest.
-    host_port_map: dict[str, int]
+    # Per-bottle docker subnet for the sidecar bundle container.
+    # The bundle runs at `bundle_ip` (always `.2`); the gateway is
+    # at `.1`. smolvm's TSI allowlist is set to `bundle_ip/32`.
+    bundle_subnet: str
+    bundle_gateway: str
+    bundle_ip: str
 
     def print(self, *, remote_control: bool) -> None:
         """Compact y/N preflight. Same shape as the Docker