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_egress.py

@@ -133,19 +133,6 @@ class TestRoutesForBottleManifestOnly(unittest.TestCase):
         effective = [r.host for r in egress_routes_for_bottle(b)]
         self.assertEqual(["x.example"], effective)
 
-    def test_tls_passthrough_lifted_from_manifest(self):
-        b = _bottle([{
-            "host": "api.openai.com",
-            "auth": {"scheme": "Bearer", "token_ref": "T"},
-            "pipelock": {"tls_passthrough": True},
-        }])
-        routes = egress_routes_for_bottle(b)
-        self.assertTrue(routes[0].tls_passthrough)
-
-    def test_tls_passthrough_false_by_default(self):
-        b = _bottle([{"host": "api.github.com"}])
-        routes = egress_routes_for_bottle(b)
-        self.assertFalse(routes[0].tls_passthrough)
 
 
 class TestProviderRouteMerge(unittest.TestCase):