Add third-party self-referential relations

Introduce a self-referential many-to-many relation table so a
third party can have child third parties. Each relation is
directional (parent to child); both directions can coexist as
independent rows.

Add a first_level boolean on third_parties (default true) with
a filter on the list page that defaults to showing only
first-level third parties.

Frontend adds a "Third Parties" tab on the detail page where
users can link existing third parties or create new ones from
the common third party catalog (created as non-first-level).
The list page gets a First Level/All toggle filter.

Signed-off-by: Sacha Al Himdani <sacha@getprobo.com>

apps/console/src/components/form/ThirdPartiesMultiSelectField.tsx

@@ -24,6 +24,7 @@ type ThirdParty = {
   id: string;
   name: string;
   websiteUrl: string | null | undefined;
+  firstLevel?: boolean;
 };
 
 type Props<T extends FieldValues = FieldValues> = {
@@ -66,7 +67,7 @@ function ThirdPartiesMultiSelectWithQuery<T extends FieldValues = FieldValues>(
   const thirdParties = useThirdParties(organizationId);
   const [isOpen, setIsOpen] = useState(false);
 
-  const allThirdParties = [...thirdParties];
+  const allThirdParties: ThirdParty[] = [...thirdParties];
   if (props.disabled) {
     selectedThirdParties.forEach((selectedThirdParty) => {
       if (!allThirdParties.find(v => v.id === selectedThirdParty.id)) {