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/current_model.py

@@ -0,0 +1,66 @@
+"""
+Current (linear) pricing model.
+
+Ported from eau.py:256-354 (CurrentModel).
+Pure Python + numpy, no matplotlib.
+"""
+
+from dataclasses import dataclass
+
+from app.engine.pricing import HouseholdData
+
+
+@dataclass
+class LinearTariffResult:
+    """Result of the linear tariff computation."""
+    p0: float  # flat price per m³
+    curve_volumes: list[float]
+    curve_bills_rp: list[float]
+    curve_bills_rs: list[float]
+    curve_price_m3_rp: list[float]
+    curve_price_m3_rs: list[float]
+
+
+def compute_linear_tariff(
+    households: list[HouseholdData],
+    recettes: float,
+    abop: float,
+    abos: float,
+    vmax: float = 2100,
+    nbpts: int = 200,
+) -> LinearTariffResult:
+    """
+    Compute the linear (current) pricing model.
+
+    p0 = (recettes - Σ abo) / Σ volume
+    """
+    total_abo = 0.0
+    total_volume = 0.0
+
+    for h in households:
+        abo = abos if h.status == "RS" else abop
+        total_abo += abo
+        total_volume += max(h.volume_m3, 1e-5)
+
+    if total_abo >= recettes or total_volume == 0:
+        p0 = 0.0
+    else:
+        p0 = (recettes - total_abo) / total_volume
+
+    # Generate curves
+    import numpy as np
+    vv = np.linspace(1e-5, vmax, nbpts)
+
+    bills_rp = abop + p0 * vv
+    bills_rs = abos + p0 * vv
+    price_m3_rp = abop / vv + p0
+    price_m3_rs = abos / vv + p0
+
+    return LinearTariffResult(
+        p0=p0,
+        curve_volumes=vv.tolist(),
+        curve_bills_rp=bills_rp.tolist(),
+        curve_bills_rs=bills_rs.tolist(),
+        curve_price_m3_rp=price_m3_rp.tolist(),
+        curve_price_m3_rs=price_m3_rs.tolist(),
+    )