fix:거래처코드 검색을 고유번호(id) 기반으로 변경

- Client::searchByCodeOrName → searchByIdOrName으로 변경
- 검색 기준: id(숫자일 때 정확 매칭) + name(LIKE 검색)
- 반환값: client_code 대신 id를 code로 반환

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/Http/Controllers/Barobill/EaccountController.php

@@ -951,12 +951,12 @@ public function searchClients(Request $request): JsonResponse
                 ]);
             }
 
-            $clients = Client::searchByCodeOrName($tenantId, $keyword);
+            $clients = Client::searchByIdOrName($tenantId, $keyword);
 
             return response()->json([
                 'success' => true,
                 'data' => $clients->map(fn($c) => [
-                    'code' => $c->client_code,
+                    'code' => (string) $c->id,
                     'name' => $c->name,
                 ])
             ]);