feat: scaffold backend Python project (Quart + SQLAlchemy + Celery deps)

Pins runtime and ML deps separately so the regular web image stays lean.
Configures ruff for py312 with bugbear, async, and pyupgrade lints enabled.
psycopg sync driver included up-front for alembic.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

pyproject.toml

@@ -0,0 +1,9 @@
+[project]
+name = "fabledcurator"
+version = "0.1.0"
+description = "FabledSword family — self-hosted media curation, gallery, ML tagging, and subscription-driven downloads."
+requires-python = ">=3.12"
+
+[tool.setuptools.packages.find]
+where = ["."]
+include = ["backend*"]