feat: Kontakt-Ordner mit Drag&Drop Baum (wie KI-Chat Sidebar)

- Backend: ContactFolder model (hierarchisch, parent_id, sort_order)
- Migration 0022: contact_folders Tabelle + folder_id FK auf contacts
- CRUD Routes: /api/v1/contact-folders (list, create, update, delete, reorder)
- Move Contact API: /api/v1/contact-folders/contacts/{id}/move
- folder_id Filter in contacts list API
- Frontend: ContactFolderTree mit Baum-Struktur, Drag&Drop, Kontext-Menü
- Kontakt-Personen-Icon statt Ordner-Symbol
- ContactList Items draggable (List/Table/Cards View)
- React Query Hooks für Folder CRUD + Move Contact
- Alle 266 Frontend-Tests passing

app/routes/contact_folders.py

@@ -0,0 +1,109 @@
+"""Contact folder routes — CRUD, move contacts, reorder."""
+
+from __future__ import annotations
+
+import uuid
+
+from fastapi import APIRouter, Depends, HTTPException, status
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.core.db import get_db
+from app.deps import require_permission
+from app.schemas.contact_folder import (
+    ContactFolderCreate,
+    ContactFolderUpdate,
+    MoveContactRequest,
+)
+from app.services import contact_folder_service
+
+router = APIRouter(prefix="/api/v1/contact-folders", tags=["contact-folders"])
+
+
+@router.get("")
+async def list_folders(
+    db: AsyncSession = Depends(get_db),
+    current_user: dict = Depends(require_permission("contacts:read")),
+):
+    """List all contact folders for the current user."""
+    tenant_id = uuid.UUID(current_user["tenant_id"])
+    user_id = uuid.UUID(current_user["user_id"])
+    return await contact_folder_service.list_folders(db, tenant_id, user_id)
+
+
+@router.post("", status_code=status.HTTP_201_CREATED)
+async def create_folder(
+    body: ContactFolderCreate,
+    db: AsyncSession = Depends(get_db),
+    current_user: dict = Depends(require_permission("contacts:write")),
+):
+    """Create a new contact folder."""
+    tenant_id = uuid.UUID(current_user["tenant_id"])
+    user_id = uuid.UUID(current_user["user_id"])
+    return await contact_folder_service.create_folder(
+        db, tenant_id, user_id, body.name, body.parent_id
+    )
+
+
+@router.put("/{folder_id}")
+async def update_folder(
+    folder_id: str,
+    body: ContactFolderUpdate,
+    db: AsyncSession = Depends(get_db),
+    current_user: dict = Depends(require_permission("contacts:write")),
+):
+    """Update a contact folder (name, parent, sort_order)."""
+    tenant_id = uuid.UUID(current_user["tenant_id"])
+    user_id = uuid.UUID(current_user["user_id"])
+    data = body.model_dump(exclude_none=True)
+    try:
+        return await contact_folder_service.update_folder(
+            db, tenant_id, user_id, folder_id, data
+        )
+    except ValueError as e:
+        raise HTTPException(status_code=404, detail=str(e))
+
+
+@router.delete("/{folder_id}", status_code=status.HTTP_204_NO_CONTENT)
+async def delete_folder(
+    folder_id: str,
+    db: AsyncSession = Depends(get_db),
+    current_user: dict = Depends(require_permission("contacts:write")),
+):
+    """Delete a contact folder. Contacts are unassigned."""
+    tenant_id = uuid.UUID(current_user["tenant_id"])
+    user_id = uuid.UUID(current_user["user_id"])
+    try:
+        await contact_folder_service.delete_folder(db, tenant_id, user_id, folder_id)
+    except ValueError as e:
+        raise HTTPException(status_code=404, detail=str(e))
+
+
+@router.put("/{folder_id}/reorder")
+async def reorder_folders(
+    folder_id: str,
+    body: list[dict],
+    db: AsyncSession = Depends(get_db),
+    current_user: dict = Depends(require_permission("contacts:write")),
+):
+    """Batch reorder folders. Body: [{id, sort_order, parent_id?}, ...]."""
+    tenant_id = uuid.UUID(current_user["tenant_id"])
+    user_id = uuid.UUID(current_user["user_id"])
+    await contact_folder_service.reorder_folders(db, tenant_id, user_id, body)
+    return {"ok": True}
+
+
+@router.put("/contacts/{contact_id}/move")
+async def move_contact(
+    contact_id: str,
+    body: MoveContactRequest,
+    db: AsyncSession = Depends(get_db),
+    current_user: dict = Depends(require_permission("contacts:write")),
+):
+    """Move a contact to a folder (or unassign with folder_id=null)."""
+    tenant_id = uuid.UUID(current_user["tenant_id"])
+    try:
+        return await contact_folder_service.move_contact(
+            db, tenant_id, contact_id, body.folder_id
+        )
+    except ValueError as e:
+        raise HTTPException(status_code=404, detail=str(e))