Multi-tenancy : espaces de travail + fix auth reload (rate limiter OPTIONS)

- Modèles Organization + OrgMember, migration Alembic (SQLite compatible)
- organization_id nullable sur Document, Decision, Mandate, VotingProtocol
- Service, schéma, router /organizations + dependency get_active_org_id
- Seed : Duniter G1 + Axiom Team ; tout le contenu seed attaché à Duniter G1
- Backend : list/create filtrés par header X-Organization
- Frontend : store organizations, WorkspaceSelector réel, useApi injecte l'org
- Fix critique : rate_limiter exclut les requêtes OPTIONS (CORS preflight)
  → résout le bug "Failed to fetch /auth/me" au reload (429 sur preflight)

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

backend/app/routers/decisions.py

@@ -21,6 +21,7 @@ from app.schemas.decision import (
     DecisionUpdate,
 )
 from app.schemas.vote import VoteSessionOut
+from app.dependencies.org import get_active_org_id
 from app.services.auth_service import get_current_identity
 from app.services.decision_service import advance_decision, create_vote_session_for_step
 
@@ -49,6 +50,7 @@ async def _get_decision(db: AsyncSession, decision_id: uuid.UUID) -> Decision:
 @router.get("/", response_model=list[DecisionOut])
 async def list_decisions(
     db: AsyncSession = Depends(get_db),
+    org_id: uuid.UUID | None = Depends(get_active_org_id),
     decision_type: str | None = Query(default=None, description="Filtrer par type de decision"),
     status_filter: str | None = Query(default=None, alias="status", description="Filtrer par statut"),
     skip: int = Query(default=0, ge=0),
@@ -57,6 +59,8 @@ async def list_decisions(
     """List all decisions with optional filters."""
     stmt = select(Decision).options(selectinload(Decision.steps))
 
+    if org_id is not None:
+        stmt = stmt.where(Decision.organization_id == org_id)
     if decision_type is not None:
         stmt = stmt.where(Decision.decision_type == decision_type)
     if status_filter is not None:
@@ -74,11 +78,13 @@ async def create_decision(
     payload: DecisionCreate,
     db: AsyncSession = Depends(get_db),
     identity: DuniterIdentity = Depends(get_current_identity),
+    org_id: uuid.UUID | None = Depends(get_active_org_id),
 ) -> DecisionOut:
     """Create a new decision process."""
     decision = Decision(
         **payload.model_dump(),
         created_by_id=identity.id,
+        organization_id=org_id,
     )
     db.add(decision)
     await db.commit()