Add interactive citizen page with sidebar, display settings, and adaptive CSS

Major rework of the citizen-facing page:
- Chart + sidebar layout (auth/vote/countdown in right sidebar)
- DisplaySettings component (font size, chart density, color palettes)
- Adaptive CSS with clamp() throughout, responsive breakpoints at 480/768/1024
- Baseline charts zoomed on first tier for small consumption detail
- Marginal price chart with dual Y-axes (foyers left, €/m³ right)
- Key metrics banner (5 columns: recettes, palier, prix palier, prix médian, mon prix)
- Client-side p0/impacts computation, draggable median price bar
- Household dots toggle, vote overlay curves
- Auth returns volume_m3, vote captures submitted_at
- Cleaned header nav (removed Accueil/Super Admin for public visitors)
- Terminology: foyer for bills, électeur for votes
- 600m³ added to impact reference volumes
- Realistic seed votes (50 votes, 3 profiles)

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

backend/app/schemas/schemas.py

@@ -21,6 +21,7 @@ class Token(BaseModel):
     token_type: str = "bearer"
     role: str
     commune_slug: str | None = None
+    volume_m3: float | None = None
 
 
 # ── Commune ──
@@ -58,6 +59,7 @@ class TariffParamsUpdate(BaseModel):
     recettes: float | None = None
     pmax: float | None = None
     vmax: float | None = None
+    differentiated_tariff: bool | None = None
     data_year: int | None = None
 
 
@@ -67,12 +69,30 @@ class TariffParamsOut(BaseModel):
     recettes: float
     pmax: float
     vmax: float
+    differentiated_tariff: bool = False
     data_year: int | None = None
     data_imported_at: datetime | None = None
+    published_vinf: float | None = None
+    published_a: float | None = None
+    published_b: float | None = None
+    published_c: float | None = None
+    published_d: float | None = None
+    published_e: float | None = None
+    published_p0: float | None = None
+    published_at: datetime | None = None
 
     model_config = {"from_attributes": True}
 
 
+class PublishCurveRequest(BaseModel):
+    vinf: float = Field(ge=0)
+    a: float = Field(ge=0, le=1)
+    b: float = Field(ge=0, le=1)
+    c: float = Field(ge=0, le=1)
+    d: float = Field(ge=0, le=1)
+    e: float = Field(ge=0, le=1)
+
+
 # ── Household ──
 
 class HouseholdOut(BaseModel):