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/cli/start.py

@@ -29,7 +29,7 @@ from ..bottle_state import (
     is_preserved,
     mark_preserved,
 )
-from ..backend.docker.capability_apply import snapshot_transcript
+# from ..backend.docker.capability_apply import snapshot_transcript
 from ..log import info
 from ..manifest import Manifest
 from ._common import PROG, USER_CWD, read_tty_line
@@ -172,7 +172,7 @@ def capture_claude_session_state(identity: str, exit_code: int) -> None:
     # instead of relying on each agent's transcript layout.
     if not identity:
         return
-    snapshot_transcript(identity)
+    # snapshot_transcript(identity)
     if exit_code != 0:
         mark_preserved(identity)