feat: allow 'all' for policy source and destination zones

backend/app/schemas.py

@@ -89,8 +89,8 @@ class InterfaceOut(BaseModel):
 
 # --- Policy ---
 class PolicyCreate(BaseModel):
-    src_zone_id: int
-    dst_zone_id: int
+    src_zone_id: Optional[int] = None
+    dst_zone_id: Optional[int] = None
     policy: str
     log_level: str = ""
     comment: str = ""
@@ -109,8 +109,8 @@ class PolicyUpdate(BaseModel):
 class PolicyOut(BaseModel):
     id: int
     config_id: int
-    src_zone_id: int
-    dst_zone_id: int
+    src_zone_id: Optional[int]
+    dst_zone_id: Optional[int]
     policy: str
     log_level: str
     comment: str