test: improve test infrastructure and fix integration tests

- Add folder to library before scanning in fsnotify integration test
- Update API endpoint paths from /items to /media-items
- Refactor test server setup to support WebSocket hijacking
- Add JobsHandler to test server configuration
- Implement proper job status polling instead of fixed delays
- Consolidate addFolderToLibrary helper into test_helpers.go
- Remove duplicate helper function from media_item_isbn_test.go
- Add error logging for search test failures
- Improve test robustness with better nil handling and type assertions
- Update worker test to use EnqueueJob and poll for completion
- Add global worker instance reset in test cleanup
- Fix media_scanner_test to initialize folders before testing

cmd/server/tests/media_item_isbn_test.go

@@ -41,27 +41,6 @@ func createTestLibrary(t *testing.T, ts *httptest.Server, token, name string) st
 	return result["id"].(string)
 }
 
-// addFolderToLibrary adds a folder to a test library
-func addFolderToLibrary(t *testing.T, ts *httptest.Server, token, libraryID, folderPath string) {
-	t.Helper()
-
-	payload := map[string]interface{}{
-		"folder_path": folderPath,
-	}
-
-	body, _ := json.Marshal(payload)
-	req, _ := http.NewRequest("POST", ts.URL+"/api/libraries/"+libraryID+"/folders", bytes.NewBuffer(body))
-	req.Header.Set("Content-Type", "application/json")
-	req.Header.Set("Authorization", "Bearer "+token)
-
-	client := &http.Client{}
-	resp, err := client.Do(req)
-	require.NoError(t, err)
-	defer resp.Body.Close()
-
-	require.Equal(t, http.StatusCreated, resp.StatusCode)
-}
-
 // TestMediaItemISBNNormalization tests ISBN normalization with media-items endpoint
 func TestMediaItemISBNNormalization(t *testing.T) {
 	setup := setupTestServer(t)
@@ -71,7 +50,7 @@ func TestMediaItemISBNNormalization(t *testing.T) {
 	libID := createTestLibrary(t, setup.Server, token, "test-isbn-lib")
 
 	// Add a folder to the library (required before adding media items)
-	addFolderToLibrary(t, setup.Server, token, libID, "/app/uploads")
+	addFolderToLibrary(t, setup, libID, "/app/uploads")
 
 	// Test ISBN normalization cases
 	testCases := []struct {
@@ -211,7 +190,7 @@ func TestMediaItemISBNEdgeCases(t *testing.T) {
 
 	token := setup.Token
 	libID := createTestLibrary(t, setup.Server, token, "test-isbn-edge-lib")
-	addFolderToLibrary(t, setup.Server, token, libID, "/app/uploads")
+	addFolderToLibrary(t, setup, libID, "/app/uploads")
 
 	t.Run("Empty ISBN should be accepted", func(t *testing.T) {
 		payload := map[string]interface{}{
@@ -296,7 +275,7 @@ func TestMediaItemsPagination(t *testing.T) {
 
 	token := setup.Token
 	libID := createTestLibrary(t, setup.Server, token, "test-pagination-lib")
-	addFolderToLibrary(t, setup.Server, token, libID, "/app/uploads")
+	addFolderToLibrary(t, setup, libID, "/app/uploads")
 
 	// Create some test media items
 	for i := 1; i <= 5; i++ {
@@ -433,7 +412,7 @@ func TestMediaItemLibraryRequirement(t *testing.T) {
 
 	t.Run("Create media-item with existing library should succeed", func(t *testing.T) {
 		libID := createTestLibrary(t, setup.Server, token, "test-req-lib")
-		addFolderToLibrary(t, setup.Server, token, libID, "/app/uploads")
+		addFolderToLibrary(t, setup, libID, "/app/uploads")
 
 		payload := map[string]interface{}{
 			"title":      "Valid Book",
@@ -471,7 +450,7 @@ func TestUpdateMediaItemISBN(t *testing.T) {
 
 	token := setup.Token
 	libID := createTestLibrary(t, setup.Server, token, "test-update-lib")
-	addFolderToLibrary(t, setup.Server, token, libID, "/app/uploads")
+	addFolderToLibrary(t, setup, libID, "/app/uploads")
 
 	// First create a media item
 	createPayload := map[string]interface{}{