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/smolmachines/bottle_plan.py

@@ -12,7 +12,6 @@ from dataclasses import dataclass
 from pathlib import Path
 
 from ...agent_provider import PromptMode
-from ...pipelock import PipelockProxyPlan
 from .. import BottlePlan
 
 
@@ -71,7 +70,6 @@ class SmolmachinesBottlePlan(BottlePlan):
     # docker's `--internal` + egress bridge topology; it's on a
     # per-bottle bridge with a pinned IP. The unused fields stay
     # at their dataclass defaults.
-    proxy_plan: PipelockProxyPlan
     # Agent-side endpoints. On Docker Desktop the docker bridge
     # IPs aren't reachable from the smolvm guest (TSI uses macOS
     # networking; docker container IPs live in the daemon's VM),