Refonte design : 4 humeurs, onboarding, sections avec boite a outils

- Systeme de themes adaptatifs : Peps (light chaud), Zen (light calme),
  Chagrine (dark violet), Grave (dark ambre) avec CSS custom properties
- Dashboard d'accueil orienté onboarding avec cartes-portes et teaser
  boite a outils
- SectionLayout reutilisable : liste + sidebar toolbox + status pills
  cliquables (En prepa / En vote / En vigueur / Clos)
- ToolboxVignette : vignettes Contexte / Tutos / Choisir / Demarrer
- Seed : Acte engagement certification + forgeron, Runtime Upgrade
  (decision on-chain), 3 modalites de vote (majoritaire, quadratique,
  permanent)
- Backend adapte SQLite (Uuid portable, 204 fix, pool conditionnel)
- Correction noms composants (pathPrefix: false), pinia/nuxt ^0.11

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

backend/app/database.py

@@ -3,14 +3,25 @@ from sqlalchemy.orm import DeclarativeBase
 
 from app.config import settings
 
-engine = create_async_engine(
-    settings.DATABASE_URL,
-    echo=settings.ENVIRONMENT == "development",
-    pool_size=settings.DATABASE_POOL_SIZE,
-    max_overflow=settings.DATABASE_MAX_OVERFLOW,
-    pool_pre_ping=True,
-    pool_recycle=3600,
-)
+_is_sqlite = settings.DATABASE_URL.startswith("sqlite")
+
+# SQLite doesn't support pool_size/max_overflow/pool_pre_ping/pool_recycle
+if _is_sqlite:
+    engine = create_async_engine(
+        settings.DATABASE_URL,
+        echo=settings.ENVIRONMENT == "development",
+        connect_args={"check_same_thread": False},
+    )
+else:
+    engine = create_async_engine(
+        settings.DATABASE_URL,
+        echo=settings.ENVIRONMENT == "development",
+        pool_size=settings.DATABASE_POOL_SIZE,
+        max_overflow=settings.DATABASE_MAX_OVERFLOW,
+        pool_pre_ping=True,
+        pool_recycle=3600,
+    )
+
 async_session = async_sessionmaker(engine, class_=AsyncSession, expire_on_commit=False)