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/integration/test_smolmachines_launch.py

@@ -124,32 +124,6 @@ class TestSmolmachinesLaunch(unittest.TestCase):
             f"expected a connect-refusal message; got: {r.stdout!r}",
         )
 
-    def test_pipelock_answers_on_bundle_ip(self):
-        # Chunk 4b: the bundle's pipelock daemon is now actually
-        # running (was daemons_csv="" in chunks 2d/3). From inside
-        # the guest, a TCP connect to <bundle-ip>:8888 must succeed
-        # — distinct from the egress-port-bypass probe below where
-        # the connect must FAIL.
-        #
-        # We don't try to speak proxy protocol here — pipelock will
-        # 4xx a bare GET — we just verify the socket answers.
-        r = self.bottle.exec(
-            f"wget -T 5 -t 1 -O - http://{self.plan.bundle_ip}:8888/ "
-            "2>&1 || true"
-        )
-        # Any HTTP response (even a 4xx) proves pipelock is up.
-        # "connection refused" / "unable to connect" / "timed out"
-        # would mean it isn't.
-        msg = r.stdout.lower()
-        self.assertNotIn(
-            "connection refused", msg,
-            f"pipelock connect refused — daemon not listening? {r.stdout!r}",
-        )
-        self.assertNotIn(
-            "timed out", msg,
-            f"pipelock connect timed out: {r.stdout!r}",
-        )
-
     def test_prompt_file_lands_in_guest(self):
         # provision_prompt copies the host-side prompt.txt into the
         # guest at /root/.bot-bottle-prompt.txt. The content