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/sidecar_bundle.py

@@ -19,7 +19,7 @@ This module ships the lifecycle primitives only — create
 network, start bundle, stop bundle, remove network — wrapped
 around `subprocess.run(["docker", ...])`. Wiring them into the
 launch flow + populating the `BundleLaunchSpec` from the inner
-Plans (PipelockProxyPlan, EgressPlan, …) lands in chunk 2d."""
+Plans (EgressPlan, …) lands in chunk 2d."""
 
 from __future__ import annotations
 
@@ -69,7 +69,7 @@ class BundleLaunchSpec:
     # Daemon subset CSV for BOT_BOTTLE_SIDECAR_DAEMONS. The
     # supervisor inside the bundle reads it to skip
     # bottle-irrelevant daemons (e.g. supervise=False bottles).
-    daemons_csv: str = "egress,pipelock"
+    daemons_csv: str = "egress"
     # Plain "KEY=VALUE" strings + "KEY" bare names (the bare-name
     # form inherits the value from the docker-run subprocess env,
     # matching the docker backend's compose-up secret-forwarding