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>

tests/unit/test_docker_provision_git_user.py

@@ -20,7 +20,6 @@ from bot_bottle.backend.docker.provision import git as _git
 from bot_bottle.egress import EgressPlan
 from bot_bottle.git_gate import GitGatePlan
 from bot_bottle.manifest import Manifest
-from bot_bottle.pipelock import PipelockProxyPlan
 from bot_bottle.workspace import workspace_plan
 
 
@@ -53,9 +52,6 @@ def _plan(*, git_user: dict | None = None,  # type: ignore
         env_file=Path("/tmp/agent.env"),
         forwarded_env={},
         prompt_file=Path("/tmp/prompt.txt"),
-        proxy_plan=PipelockProxyPlan(
-            yaml_path=Path("/tmp/pipelock.yaml"), slug="demo-abc12",
-        ),
         git_gate_plan=GitGatePlan(
             slug="demo-abc12",
             entrypoint_script=Path("/tmp/git-gate-entrypoint.sh"),