refactor: rename project to winnow

- Rename Python package directory if_curator/ → winnow/
- Update all imports, entry points, and CLI references
- Update pyproject.toml: name, scripts, package list, repository URL
- Update Dockerfile, compose.yml, entrypoint.sh, scheduler.py
- Update GitHub Actions workflow image names
- Update README

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

winnow/__init__.py

@@ -0,0 +1,8 @@
+"""Immich to Frigate training set curator.
+
+AI-powered tool to extract high-quality, diverse training images from your
+Immich library for Frigate's Face Recognition (ArcFace) and Object/State
+Classification models.
+"""
+
+__version__ = "0.1.0"