fix(tests): make collection names unique in bulk operations tests

- Fix TestCollectionsBulkOperations/BulkAddBooks_SingleOperation failure
- Each subtest was creating "Test Collection" with same name
- Collections table has UNIQUE(user_id, name) constraint causing 500 errors
- Made collection names unique by adding test name suffix:
  - Test Collection - InvalidBookID
  - Test Collection - SingleOperation
  - Test Collection - MultipleBooksSingleCollection
  - Test Collection 1 - MultipleCollections
  - Test Collection 2 - MultipleCollections
  - Test Collection - DuplicateBooks

This preserves test data for manual API testing with Bruno while
ensuring test isolation and preventing unique constraint violations.

cmd/server/tests/collections_bulk_test.go

@@ -96,7 +96,7 @@ func TestCollectionsBulkOperations(t *testing.T) {
 	t.Run("BulkAddBooks_InvalidBookID", func(t *testing.T) {
 		// Create a collection first
 		collectionReq := map[string]interface{}{
-			"name":        "Test Collection",
+			"name":        "Test Collection - InvalidBookID",
 			"description": "A test collection",
 		}
 		collectionBody, _ := json.Marshal(collectionReq)
@@ -145,7 +145,7 @@ func TestCollectionsBulkOperations(t *testing.T) {
 	t.Run("BulkAddBooks_SingleOperation", func(t *testing.T) {
 		// Create a collection
 		collectionReq := map[string]interface{}{
-			"name":        "Test Collection",
+			"name":        "Test Collection - SingleOperation",
 			"description": "A test collection",
 		}
 		collectionBody, _ := json.Marshal(collectionReq)
@@ -202,7 +202,7 @@ func TestCollectionsBulkOperations(t *testing.T) {
 	t.Run("BulkAddBooks_MultipleBooksSingleCollection", func(t *testing.T) {
 		// Create a collection
 		collectionReq := map[string]interface{}{
-			"name":        "Test Collection",
+			"name":        "Test Collection - MultipleBooksSingleCollection",
 			"description": "A test collection",
 		}
 		collectionBody, _ := json.Marshal(collectionReq)
@@ -255,7 +255,7 @@ func TestCollectionsBulkOperations(t *testing.T) {
 	t.Run("BulkAddBooks_MultipleCollections", func(t *testing.T) {
 		// Create multiple collections
 		collectionReq := map[string]interface{}{
-			"name":        "Test Collection 1",
+			"name":        "Test Collection 1 - MultipleCollections",
 			"description": "First test collection",
 		}
 		collectionBody, _ := json.Marshal(collectionReq)
@@ -273,7 +273,7 @@ func TestCollectionsBulkOperations(t *testing.T) {
 		collectionID1 := collectionResult1["id"].(string)
 
 		collectionReq2 := map[string]interface{}{
-			"name":        "Test Collection 2",
+			"name":        "Test Collection 2 - MultipleCollections",
 			"description": "Second test collection",
 		}
 		collectionBody2, _ := json.Marshal(collectionReq2)
@@ -329,7 +329,7 @@ func TestCollectionsBulkOperations(t *testing.T) {
 	t.Run("BulkAddBooks_DuplicateBooks", func(t *testing.T) {
 		// Create a collection
 		collectionReq := map[string]interface{}{
-			"name":        "Test Collection",
+			"name":        "Test Collection - DuplicateBooks",
 			"description": "A test collection",
 		}
 		collectionBody, _ := json.Marshal(collectionReq)