fix: resolve all linting errors, add tests, bump base image

Linting (ruff):
- cli.py: sort relative imports (I001)
- jobs.py: remove unused get_people import (F401), wrap long line (E501)
- executor.py: remove unused success variable (F841), wrap 4 long lines (E501)

Tests (24 passing):
- tests/test_config.py: config singleton defaults + env var overrides
- tests/test_upload_tracker.py: mark/filter/reset/summary logic
- tests/test_immich_api.py: filter_recent_assets date boundary cases
- tests/test_jobs.py: _resolve_strategy with LIMIT env var and fallbacks
- pyproject.toml: add [tool.pytest.ini_options] testpaths=["tests"] so
  pytest doesn't scan .venv in CI

Security:
- Dockerfile: bump CUDA base from 12.6.3 to 12.9.2 to pick up patched
  Ubuntu packages (fixes Dependabot low-severity alert)

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

if_curator/cli.py

@@ -7,11 +7,11 @@ from rich import print as rprint
 from rich.prompt import Confirm
 
 from .config import Config, ConfigManager
+from .executor import execute_jobs, upload_to_frigate
 from .immich_api import get_people
+from .jobs import _show_preview, auto_configure, interactive_configure
 from .logging import console, setup_logging
 from .upload_tracker import get_person_summary, reset_person
-from .executor import execute_jobs, upload_to_frigate
-from .jobs import auto_configure, interactive_configure, _show_preview
 
 logger = logging.getLogger(__name__)