feat(backend): initialisation du projet FastAPI

Structure en couches api / services / repositories / models, sens de
dependance unique, une session SQLAlchemy async injectee par dependance.

- Python 3.14, dependances gerees par uv et verrouillees dans uv.lock
- FastAPI expose par une factory : aucune configuration lue a l'import,
  ce qui rend tests et migrations independants de l'environnement
- Settings Pydantic, APP_SECRET_KEY et DATABASE_URL sans valeur par defaut
- Sondes /health/live et /health/ready, metriques Prometheus sur /metrics
- Lint et format ruff, mypy strict, pytest avec couverture
- Alembic branche sur DATABASE_URL et non sur alembic.ini
- Image Docker multi-stage, utilisateur non root, sonde de sante integree

apps/backend/pyproject.toml

@@ -0,0 +1,86 @@
+[project]
+name = "enervision-backend"
+version = "0.1.0"
+description = "API EnerVision : exposition des series temporelles energetiques"
+requires-python = ">=3.14,<3.15"
+dependencies = [
+    "fastapi>=0.141.1",
+    "uvicorn[standard]>=0.53.0",
+    "pydantic>=2.13.5",
+    "pydantic-settings>=2.15.0",
+    "sqlalchemy[asyncio]>=2.0.52",
+    "asyncpg>=0.31.0",
+    "alembic>=1.20.0",
+    "prometheus-fastapi-instrumentator>=8.1.0",
+    "python-json-logger>=4.2.0",
+]
+
+[dependency-groups]
+dev = [
+    "ruff>=0.16.7",
+    "mypy>=2.3.1",
+    "pytest>=9.1.1",
+    "pytest-asyncio>=1.4.0",
+    "pytest-cov>=7.1.0",
+    "httpx>=0.28.1",
+]
+
+[build-system]
+requires = ["hatchling>=1.32.0"]
+build-backend = "hatchling.build"
+
+[tool.hatch.build.targets.wheel]
+packages = ["app"]
+
+[tool.ruff]
+line-length = 100
+target-version = "py314"
+src = ["app", "tests"]
+extend-exclude = ["alembic/versions"]
+
+[tool.ruff.lint]
+select = [
+    "E", "W",
+    "F",
+    "I",
+    "N",
+    "UP",
+    "B",
+    "C4",
+    "SIM",
+    "TID",
+    "RUF",
+    "ASYNC",
+    "S",
+    "PT",
+]
+ignore = ["B008"]
+
+[tool.ruff.lint.per-file-ignores]
+"tests/**/*.py" = ["S101"]
+
+[tool.ruff.lint.isort]
+known-first-party = ["app"]
+
+[tool.ruff.format]
+quote-style = "double"
+
+[tool.mypy]
+python_version = "3.14"
+strict = true
+warn_unreachable = true
+plugins = ["pydantic.mypy"]
+exclude = ["^alembic/"]
+
+[[tool.mypy.overrides]]
+module = ["tests.*"]
+disallow_untyped_defs = false
+
+[tool.pytest.ini_options]
+testpaths = ["tests"]
+asyncio_mode = "auto"
+addopts = "-q --strict-markers --cov=app --cov-report=term-missing"
+
+[tool.coverage.run]
+source = ["app"]
+omit = ["app/main.py", "alembic/*"]