fix(container-returns): dedupe company names in the return picker

freight.companies allows duplicate names, and Mantine v9 throws on duplicate
Autocomplete option values, taking down the whole Container Returns page with
a render error.

Dedupes the option list by trimmed name. resolveId now returns an id only
when exactly one company carries the name — an ambiguous name resolves to
nothing, so the return keeps the typed company name rather than silently
attaching to whichever duplicate happened to come first.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

apps/edr-freight-web/backoffice/src/components/warehouses/useCompanyOptions.ts

@@ -16,11 +16,22 @@ export function useCompanyOptions() {
 
   const companies = data?.items ?? [];
 
+  // Company names are not unique — Mantine throws on duplicate option values,
+  // so the list is deduped by the trimmed name.
+  const names = [...new Set(companies.map((c) => c.name.trim()).filter(Boolean))];
+
   return {
     loading: isLoading,
-    names: companies.map((c) => c.name),
-    /** Exact (case-insensitive) name match → company id, else undefined. */
-    resolveId: (name: string): string | undefined =>
-      companies.find((c) => c.name.trim().toLowerCase() === name.trim().toLowerCase())?.id,
+    names,
+    /**
+     * Name → company id, only when exactly one company carries that name. An
+     * ambiguous name resolves to nothing rather than to an arbitrary company:
+     * the container keeps the typed name and no wrong customer is attached.
+     */
+    resolveId: (name: string): string | undefined => {
+      const key = name.trim().toLowerCase();
+      const matches = companies.filter((c) => c.name.trim().toLowerCase() === key);
+      return matches.length === 1 ? matches[0].id : undefined;
+    },
   };
 }