chore: remove all pipelock references from tests, docs, and non-pipelock source

- Strip pipelock from all unit and integration test fixtures:
  proxy_plan fields removed from DockerBottlePlan/SmolmachinesBottlePlan
  constructors; pipelock-specific test classes deleted or renamed
- Update test_sidecar_init: remove test_pipelock_loses_egress_tokens,
  rename "pipelock" daemon fixtures to "git-gate" throughout
- Remove test_pipelock_binary_present_and_versioned from integration test
- Remove test_pipelock_answers_on_bundle_ip from smolmachines launch test
- Update _SANDBOX_BLOCK_MARKERS: remove "pipelock" marker (egress blocks)
- Dockerfile.sidecars: remove pipelock build stage and COPY; update layout
  comments and port table
- egress_entrypoint.sh: update comments now that egress is sole proxy
- Clean up pipelock references in comments/docstrings across backend,
  network, manifest, supervise, git_gate, yaml_subset, agent_provider,
  sidecar_bundle, sidecar_init, egress_addon_core modules

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

bot_bottle/backend/docker/prepare.py

@@ -200,10 +200,9 @@ def resolve_plan(
         # root; for `--cwd` derived images the base Dockerfile is what
         # the agent should propose changes against (the derived layer
         # is just a workspace copy).
-        # (routes.yaml + pipelock allowlist used to land here too but
-        # PRD 0017 chunk 3 moved them behind the
-        # `list-egress-routes` MCP tool so the agent gets live
-        # state rather than a launch-time snapshot.)
+        # (routes.yaml used to land here too but PRD 0017 chunk 3
+        # moved it behind the `list-egress-routes` MCP tool so the
+        # agent gets live state rather than a launch-time snapshot.)
         supervise_dockerfile_path = (
             Path(dockerfile_path)
             if dockerfile_path