Add entity customer numbers and scope APIs via selected company.

Entity gets an optional unique-per-company number with allocate/peek/isNumberFree helpers. Company-scoped store methods no longer take companyId and resolve google_auth.selected_company instead.

API.category.md

@@ -69,7 +69,7 @@ Returns the full category tree for a company together with its articles and the
 
 ```js
 const fn = getTreeForCompany(pool);
-const tree = await fn(42, 1);
+const tree = await fn(42);
 // => { languageId, tree: [{ id, posterminalIds, ... }], articles: [...] }
 ```