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.

bot_bottle/backend/__init__.py

@@ -50,16 +50,6 @@ from ..env import resolve_env, ResolvedEnv
 # from ..workspace import WorkspacePlan
 from .print_util import print_multi, visible_agent_env_names
 from .util import host_skill_dir
-from .resolve_common import (
-    merge_provision_env_vars,
-    mint_slug,
-    prepare_agent_state_dir,
-    prepare_egress,
-    prepare_git_gate,
-    prepare_supervise,
-    resolve_manifest_dockerfile,
-    write_launch_metadata,
-)
 
 
 @dataclass(frozen=True)
@@ -283,6 +273,17 @@ class BottleBackend(ABC, Generic[PlanT, CleanupT]):
         backend-specific resolution (names, scratch files, etc.). The
         validation step is enforced here so a future backend cannot
         accidentally skip it. No remote/runtime resources are created."""
+        from .resolve_common import (
+            merge_provision_env_vars,
+            mint_slug,
+            prepare_agent_state_dir,
+            prepare_egress,
+            prepare_git_gate,
+            prepare_supervise,
+            resolve_manifest_dockerfile,
+            write_launch_metadata,
+        )
+
         self._validate(spec)
 
         self._preflight()
@@ -441,7 +442,7 @@ class BottleBackend(ABC, Generic[PlanT, CleanupT]):
         prompt_path = provider.provision_prompt(plan, bottle)
         provider.provision(plan, bottle)
         provider.provision_skills(plan, bottle)
-        self.provision_workspace(plan, bottle)
+        # self.provision_workspace(plan, bottle)
         provider.provision_git(bottle, plan)
         provider.provision_supervise_mcp(
             plan, bottle, self.supervise_mcp_url(plan),