chore: comment out workspace + capability_apply, fix circular imports

The recent refactor partially removed workspace planning and
capability-apply logic. This commit finishes the cleanup so the
test suite imports cleanly:

- Comment out workspace_plan field/property on BottlePlan and the
  provision_workspace dispatch.
- Comment out workspace usages in docker.util (build_image_with_cwd),
  smolmachines.provision.workspace, agent_provider.provision_git,
  smolmachines.backend.
- Comment out capability_apply imports in cli.start and cli.supervise;
  add a local CapabilityApplyError placeholder so the supervise CLI
  module still imports.
- Break the bottle_state → backend.docker → backend circular import
  by lazy-loading docker_mod inside bottle_identity, and by moving the
  resolve_common import inside BottleBackend.prepare.
- Delete tests for workspace and capability_apply (unit + integration).
- Update test fixtures to drop removed kwargs (container_name_pinned,
  derived_image, env_file, workspace_plan, agent_image_ref) from
  DockerBottlePlan / SmolmachinesBottlePlan constructors.
- Delete the obsolete test_smolmachines_prepare.py (tested the old
  resolve_plan signature; the shared prepare flow now lives in
  BottleBackend.prepare).
- Adjust test_supervise.py for the new Supervise.prepare signature
  (dockerfile_content arg removed).

925 → 897 tests, all passing.

tests/unit/test_supervise.py

@@ -359,25 +359,19 @@ class TestSupervisePrepare(unittest.TestCase):
         return lambda: setattr(supervise, "bot_bottle_root", original)
 
     def test_prepare_creates_queue_and_current_config(self):
-        plan = _StubSupervise().prepare(
-            "dev", self.stage_dir,
-            dockerfile_content="FROM python:3.13\n",
-        )
+        plan = _StubSupervise().prepare("dev", self.stage_dir)
         self.assertTrue(plan.queue_dir.is_dir())
         self.assertTrue(plan.current_config_dir.is_dir())
-        self.assertEqual(
-            "FROM python:3.13\n",
-            (plan.current_config_dir / "Dockerfile").read_text(),
-        )
         self.assertEqual("dev", plan.slug)
         self.assertEqual("", plan.internal_network)
 
-    def test_prepare_only_writes_dockerfile_to_current_config(self):
+    def test_prepare_writes_no_files_to_current_config(self):
+        # dockerfile_content is no longer accepted by prepare.
         # routes.yaml + allowlist live behind the
-        # `list-egress-routes` MCP tool now (PRD 0017 chunk 3).
+        # `list-egress-routes` MCP tool (PRD 0017 chunk 3).
         plan = _StubSupervise().prepare("dev", self.stage_dir)
         files = sorted(p.name for p in plan.current_config_dir.iterdir())
-        self.assertEqual(["Dockerfile"], files)
+        self.assertEqual([], files)
 
 
 if __name__ == "__main__":