feat: Projektfundament mit Datenmodell, Migrationen und Seed

- Repo-Struktur für Backend, Frontend, Dokumentation und Gitea-Workflows
- FastAPI-Skeleton mit pydantic-settings und RFC-7807-artigem Fehlerformat
- Vollständiges Datenmodell (15 Tabellen) als SQLAlchemy-2.0-Modelle
- Alembic gegen die Async-Engine inklusive Erstmigration
- Idempotenter Seed für den deutschen Kategoriebaum und Standardregeln
- Endpunkte /api/health und /api/version
- pytest-Infrastruktur mit transaktionsisolierten Fixtures

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014e7t8UpmoVNMtWivY5LiSH

backend/pyproject.toml

@@ -0,0 +1,60 @@
+[project]
+name = "moneyfy-backend"
+version = "0.1.0"
+description = "moneyfy – Planung monatlicher Kosten und Einkünfte"
+requires-python = ">=3.12,<3.13"
+dependencies = [
+    "fastapi>=0.115",
+    "uvicorn[standard]>=0.32",
+    "sqlalchemy[asyncio]>=2.0.36",
+    "asyncpg>=0.30",
+    "alembic>=1.14",
+    "pydantic>=2.10",
+    "pydantic-settings>=2.7",
+    "python-dateutil>=2.9",
+    "holidays>=0.63",
+    "apscheduler>=3.11",
+    "argon2-cffi>=23.1",
+    "pyjwt>=2.10",
+    "httpx>=0.28",
+    "pillow>=11.0",
+    "openpyxl>=3.1",
+    "apprise>=1.9",
+    "python-multipart>=0.0.20",
+    "email-validator>=2.2",
+]
+
+[project.optional-dependencies]
+dev = [
+    "pytest>=8.3",
+    "pytest-asyncio>=0.24",
+    "ruff>=0.8",
+    "psycopg[binary]>=3.2",
+    "freezegun>=1.5",
+]
+
+[build-system]
+requires = ["setuptools>=75"]
+build-backend = "setuptools.build_meta"
+
+[tool.setuptools.packages.find]
+include = ["app*"]
+
+[tool.ruff]
+line-length = 100
+target-version = "py312"
+extend-exclude = ["alembic/versions"]
+
+[tool.ruff.lint]
+select = ["E", "F", "I", "UP", "B", "SIM", "C4", "N", "RUF"]
+ignore = ["B008", "RUF001", "RUF002", "RUF003"]
+
+[tool.ruff.format]
+quote-style = "double"
+
+[tool.pytest.ini_options]
+testpaths = ["tests"]
+asyncio_mode = "auto"
+asyncio_default_fixture_loop_scope = "session"
+asyncio_default_test_loop_scope = "session"
+filterwarnings = ["ignore::DeprecationWarning"]