Initial commit: SejeteralO water tarification platform

Full-stack app for participatory water pricing using Bezier curves.
- Backend: FastAPI + SQLAlchemy + SQLite with JWT auth
- Frontend: Nuxt 4 + TypeScript with interactive SVG editor
- Math engine: cubic Bezier tarification with Cardano solver
- Admin: commune management, household import, vote monitoring, CMS
- Citizen: interactive curve editor, vote submission
- Docker-compose deployment ready

Includes fixes for:
- Impact table snake_case/camelCase property mismatch
- CMS content backend API + frontend editor (was stub)
- Admin route protection middleware
- Public content display on commune page
- Vote confirmation page link fix

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

backend/app/engine/__init__.py

@@ -0,0 +1,23 @@
+from app.engine.integrals import compute_integrals
+from app.engine.pricing import (
+    HouseholdData,
+    TariffResult,
+    compute_p0,
+    compute_tariff,
+    compute_impacts,
+)
+from app.engine.current_model import compute_linear_tariff, LinearTariffResult
+from app.engine.median import VoteParams, compute_median
+
+__all__ = [
+    "compute_integrals",
+    "HouseholdData",
+    "TariffResult",
+    "compute_p0",
+    "compute_tariff",
+    "compute_impacts",
+    "compute_linear_tariff",
+    "LinearTariffResult",
+    "VoteParams",
+    "compute_median",
+]