refactor(sidecars): bundle is the only shape (PRD 0024 chunk 5)

The CLAUDE_BOTTLE_SIDECAR_BUNDLE feature flag is gone. Every
bottle ships with the agent + bundle pair — no opt-in, no legacy
four-sidecar fallback.

Changes:

- Renderer (compose.py): bottle_plan_to_compose unconditionally
  emits {agent, sidecars}. Deleted _pipelock_service,
  _git_gate_service, _egress_service, _supervise_service helpers.
  _agent_service.depends_on collapses to ["sidecars"].

- sidecar_bundle.py: deleted sidecar_bundle_enabled (the flag
  parser). SIDECAR_BUNDLE_IMAGE + container-name helper stay.

- pipelock_apply.py: docker cp + docker restart now target
  sidecar_bundle_container_name(slug). Bundle restart bounces
  all four daemons together (per-daemon reload is the eventual
  feature, not v1).

- Per-sidecar modules trimmed:
  - egress.py: dropped EGRESS_IMAGE, EGRESS_DOCKERFILE,
    build_egress_image, egress_url. Kept EGRESS_PORT, CA paths,
    egress_container_name (still used by the renderer's network
    aliases).
  - git_gate.py: dropped GIT_GATE_IMAGE, GIT_GATE_DOCKERFILE,
    build_git_gate_image. Kept git_gate_host + GIT_GATE_PORT.
  - supervise.py: dropped SUPERVISE_IMAGE, SUPERVISE_DOCKERFILE,
    build_supervise_image, supervise_url.

- Deleted Dockerfile.{egress,git-gate,supervise}. The bundle's
  Dockerfile.sidecars is the only sidecar image now.

- test_compose.py: deleted TestPipelockAlwaysPresent,
  TestConditionalGitGate, TestConditionalEgress,
  TestConditionalSupervise, TestFullMatrix (legacy-shape only),
  TestSidecarBundleFlag (flag is gone). TestSidecarBundleShape
  drops its patch.dict wrapper. TestAgentAlwaysPresent's
  depends_on cases collapse to one.

- test_pipelock_apply.py: bringup container name uses
  sidecar_bundle_container_name(slug) to match the production
  target.

- README.md Architecture section rewritten to describe the
  agent + bundle pair.

Net: -626 lines.

Test status: 498 unit + 27 integration + 1 skipped (chunk-4
pending — superseded by this chunk's rewrite). Locally verified
end-to-end bottle launch produces exactly 2 containers
(claude-bottle-<slug> + claude-bottle-sidecars-<slug>).

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

claude_bottle/backend/docker/git_gate.py

@@ -1,56 +1,39 @@
-"""DockerGitGate — the Docker-specific lifecycle for the per-agent
-git-gate sidecar (PRD 0008). Inherits the platform-agnostic prepare
-step (upstream lift + entrypoint/hook render) from `GitGate`."""
+"""DockerGitGate — Docker-flavored git-gate config (PRD 0008).
+Inherits the platform-agnostic prepare step (upstream lift +
+entrypoint/hook render) from `GitGate`. The git-gate daemon runs
+inside the sidecar bundle (PRD 0024); this module just holds the
+in-container paths the renderer's bind-mounts target."""
 
 from __future__ import annotations
 
-import os
-from pathlib import Path
-
 from ...git_gate import GitGate
-from . import util as docker_mod
 
 
-GIT_GATE_IMAGE = os.environ.get(
-    "CLAUDE_BOTTLE_GIT_GATE_IMAGE",
-    "claude-bottle-git-gate:latest",
-)
-
-GIT_GATE_DOCKERFILE = "Dockerfile.git-gate"
-
 GIT_GATE_ENTRYPOINT_IN_CONTAINER = "/git-gate-entrypoint.sh"
 GIT_GATE_HOOK_IN_CONTAINER = "/etc/git-gate/pre-receive"
 GIT_GATE_ACCESS_HOOK_IN_CONTAINER = "/etc/git-gate/access-hook"
 GIT_GATE_CREDS_DIR_IN_CONTAINER = "/git-gate/creds"
 
-# git daemon's default listening port. Surfaced as a constant because
-# integration tests probe the gate on it.
+# git daemon's default listening port.
 GIT_GATE_PORT = 9418
 
-# Repo root, for `docker build` context. Resolved from this file's
-# location: claude_bottle/backend/docker/git_gate.py → repo root.
-_REPO_DIR = str(Path(__file__).resolve().parent.parent.parent.parent)
-
 
 def git_gate_container_name(slug: str) -> str:
+    """The legacy per-sidecar container name. Kept as a function so
+    the renderer can register it as a docker-network alias on the
+    bundle — any code still dialing `claude-bottle-git-gate-<slug>`
+    resolves to the bundle's IP."""
     return f"claude-bottle-git-gate-{slug}"
 
 
 def git_gate_host(slug: str) -> str:
-    """The hostname the agent's git client should connect to (same as
-    the container name — Docker's embedded DNS resolves it on the
-    `--internal` network)."""
+    """The hostname the agent's git client connects to. Resolves via
+    the bundle's network alias to the bundle container, where the
+    git-gate daemon listens on GIT_GATE_PORT."""
     return git_gate_container_name(slug)
 
 
-def build_git_gate_image() -> None:
-    """Build the git-gate image from `Dockerfile.git-gate`. Called by
-    `DockerGitGate.start`; exposed at module level so integration
-    tests can build it without running the full launch pipeline."""
-    docker_mod.build_image(GIT_GATE_IMAGE, _REPO_DIR, dockerfile=GIT_GATE_DOCKERFILE)
-
-
 class DockerGitGate(GitGate):
     """Docker-flavored GitGate: inherits `.prepare()` from the base.
-    Container lifecycle is owned by compose; per-container
-    `.start()` / `.stop()` were removed in PRD 0024 chunk 3."""
+    The git-gate daemon's container lifecycle is owned by the
+    sidecar bundle (PRD 0024)."""