fix(lint): resolve pyright and pylint issues in provider/backend changes

- Remove unused Bottle import from docker/backend.py (pyright)
- Suppress wrong-import-position on circular-import-avoiding
  deferred imports in backend/__init__.py (pylint C0413)
- Add encoding="utf-8" to read_text() in smolmachines provision
  test (pylint W1514)
- Suppress consider-using-with on TemporaryDirectory setUp pattern
  in both provision test files (pylint R1732)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

bot_bottle/backend/docker/backend.py

@@ -25,7 +25,7 @@ from pathlib import Path
 from typing import Generator, Sequence
 
 from ...supervise import SUPERVISE_HOSTNAME, SUPERVISE_PORT
-from .. import ActiveAgent, Bottle, BottleBackend, BottleSpec
+from .. import ActiveAgent, BottleBackend, BottleSpec
 from . import cleanup as _cleanup
 from . import enumerate as _enumerate
 from . import launch as _launch