feat(admin): implement provider-specific storage configuration pages

Refactor the admin storage backend creation and editing flows to use
provider-specific pages (e.g., `/admin/storage/new/sftp`) instead of a
single generic form. This ensures only relevant fields are rendered for
each storage provider (such as SFTP, S3, or WebDAV).

Additionally:
- Prevent mutation of the storage provider type during backend edits.
- Add comprehensive unit tests for provider-specific rendering, edit
  validation, and CSRF/admin route protection.

backend/libs/services/storage.go

@@ -16,6 +16,7 @@ import (
 )
 
 var storageBackendsBucket = []byte("storage_backends")
+var storageBackendTestStatusBucket = []byte("storage_backend_test_status")
 
 const (
 	StorageBackendLocal  = "local"
@@ -81,10 +82,12 @@ type StorageBackendConfig struct {
 }
 
 type StorageBackendView struct {
-	Config     StorageBackendConfig
-	UsageBytes int64
-	UsageLabel string
-	InUse      bool
+	Config       StorageBackendConfig
+	UsageBytes   int64
+	UsageLabel   string
+	InUse        bool
+	SpeedTests   []StorageSpeedTest
+	CanSpeedTest bool
 }
 
 type StorageService struct {
@@ -99,7 +102,13 @@ func NewStorageService(db *bbolt.DB, dataDir string) (*StorageService, error) {
 	}
 	service := &StorageService{db: db, localFilesDir: filesDir}
 	err := db.Update(func(tx *bbolt.Tx) error {
-		_, err := tx.CreateBucketIfNotExists(storageBackendsBucket)
+		if _, err := tx.CreateBucketIfNotExists(storageBackendsBucket); err != nil {
+			return err
+		}
+		if _, err := tx.CreateBucketIfNotExists(storageBackendTestStatusBucket); err != nil {
+			return err
+		}
+		_, err := tx.CreateBucketIfNotExists(storageSpeedTestsBucket)
 		return err
 	})
 	if err != nil {
@@ -126,7 +135,9 @@ func (s *StorageService) Backend(id string) (StorageBackend, error) {
 func (s *StorageService) BackendConfig(id string) (StorageBackendConfig, error) {
 	id = strings.TrimSpace(id)
 	if id == "" || id == StorageBackendLocal {
-		return s.localConfig(), nil
+		cfg := s.localConfig()
+		s.applyStoredTestStatus(&cfg)
+		return cfg, nil
 	}
 	var cfg StorageBackendConfig
 	err := s.db.View(func(tx *bbolt.Tx) error {
@@ -167,18 +178,13 @@ func (s *StorageService) ListBackendConfigs() ([]StorageBackendConfig, error) {
 }
 
 func (s *StorageService) CreateS3Backend(input StorageBackendConfig) (StorageBackendConfig, error) {
+	return s.CreateBackend(input)
+}
+
+func (s *StorageService) CreateBackend(input StorageBackendConfig) (StorageBackendConfig, error) {
 	input.ID = randomID(10)
 	input.Provider = normalizeStorageProvider(input.Provider)
-	switch input.Provider {
-	case StorageProviderSFTP:
-		input.Type = StorageBackendSFTP
-	case StorageProviderSMB:
-		input.Type = StorageBackendSMB
-	case StorageProviderWebDAV:
-		input.Type = StorageBackendWebDAV
-	default:
-		input.Type = StorageBackendS3
-	}
+	input.Type = storageTypeForProvider(input.Provider)
 	if err := normalizeStorageBackendConfig(&input, true); err != nil {
 		return StorageBackendConfig{}, err
 	}
@@ -193,6 +199,10 @@ func (s *StorageService) CreateS3Backend(input StorageBackendConfig) (StorageBac
 }
 
 func (s *StorageService) UpdateS3Backend(id string, input StorageBackendConfig) (StorageBackendConfig, error) {
+	return s.UpdateBackend(id, input)
+}
+
+func (s *StorageService) UpdateBackend(id string, input StorageBackendConfig) (StorageBackendConfig, error) {
 	current, err := s.BackendConfig(id)
 	if err != nil {
 		return StorageBackendConfig{}, err
@@ -200,18 +210,19 @@ func (s *StorageService) UpdateS3Backend(id string, input StorageBackendConfig)
 	if current.ID == StorageBackendLocal {
 		return StorageBackendConfig{}, fmt.Errorf("local storage cannot be edited")
 	}
+	current.Provider = canonicalStorageProvider(current)
+	current.Type = storageTypeForProvider(current.Provider)
+
 	input.ID = current.ID
-	input.Type = current.Type
-	input.Provider = normalizeStorageProvider(input.Provider)
-	switch input.Provider {
-	case StorageProviderSFTP:
-		input.Type = StorageBackendSFTP
-	case StorageProviderSMB:
-		input.Type = StorageBackendSMB
-	case StorageProviderWebDAV:
-		input.Type = StorageBackendWebDAV
-	default:
-		input.Type = StorageBackendS3
+	requestedProvider := normalizeStorageProvider(input.Provider)
+	requestedType := storageTypeForProvider(requestedProvider)
+	if input.Type != "" && input.Type != requestedType {
+		return StorageBackendConfig{}, fmt.Errorf("storage type cannot be changed after creation")
+	}
+	input.Provider = requestedProvider
+	input.Type = requestedType
+	if input.Provider != current.Provider || input.Type != current.Type {
+		return StorageBackendConfig{}, fmt.Errorf("storage provider cannot be changed after creation")
 	}
 	if strings.TrimSpace(input.SecretKey) == "" {
 		input.SecretKey = current.SecretKey
@@ -374,10 +385,56 @@ func (s *StorageService) TestBackend(id string) (StorageBackendConfig, error) {
 	}
 	if cfg.ID != StorageBackendLocal {
 		_ = s.SaveBackendConfig(cfg)
+	} else {
+		_ = s.saveBackendTestStatus(cfg)
 	}
 	return cfg, err
 }
 
+func (s *StorageService) applyStoredTestStatus(cfg *StorageBackendConfig) {
+	_ = s.db.View(func(tx *bbolt.Tx) error {
+		bucket := tx.Bucket(storageBackendTestStatusBucket)
+		if bucket == nil {
+			return nil
+		}
+		data := bucket.Get([]byte(cfg.ID))
+		if data == nil {
+			return nil
+		}
+		var status struct {
+			LastTestedAt    time.Time `json:"lastTestedAt,omitempty"`
+			LastTestError   string    `json:"lastTestError,omitempty"`
+			LastTestSuccess bool      `json:"lastTestSuccess,omitempty"`
+		}
+		if err := json.Unmarshal(data, &status); err != nil {
+			return nil
+		}
+		cfg.LastTestedAt = status.LastTestedAt
+		cfg.LastTestError = status.LastTestError
+		cfg.LastTestSuccess = status.LastTestSuccess
+		return nil
+	})
+}
+
+func (s *StorageService) saveBackendTestStatus(cfg StorageBackendConfig) error {
+	status := struct {
+		LastTestedAt    time.Time `json:"lastTestedAt,omitempty"`
+		LastTestError   string    `json:"lastTestError,omitempty"`
+		LastTestSuccess bool      `json:"lastTestSuccess,omitempty"`
+	}{
+		LastTestedAt:    cfg.LastTestedAt,
+		LastTestError:   cfg.LastTestError,
+		LastTestSuccess: cfg.LastTestSuccess,
+	}
+	data, err := json.Marshal(status)
+	if err != nil {
+		return err
+	}
+	return s.db.Update(func(tx *bbolt.Tx) error {
+		return tx.Bucket(storageBackendTestStatusBucket).Put([]byte(cfg.ID), data)
+	})
+}
+
 func (s *StorageService) backendFromConfig(cfg StorageBackendConfig) (StorageBackend, error) {
 	switch cfg.Type {
 	case StorageBackendLocal:
@@ -424,6 +481,35 @@ func normalizeStorageProvider(provider string) string {
 	}
 }
 
+func canonicalStorageProvider(cfg StorageBackendConfig) string {
+	if cfg.Provider != "" && cfg.Provider != StorageBackendLocal {
+		return normalizeStorageProvider(cfg.Provider)
+	}
+	switch cfg.Type {
+	case StorageBackendSFTP:
+		return StorageProviderSFTP
+	case StorageBackendSMB:
+		return StorageProviderSMB
+	case StorageBackendWebDAV:
+		return StorageProviderWebDAV
+	default:
+		return StorageProviderS3
+	}
+}
+
+func storageTypeForProvider(provider string) string {
+	switch normalizeStorageProvider(provider) {
+	case StorageProviderSFTP:
+		return StorageBackendSFTP
+	case StorageProviderSMB:
+		return StorageBackendSMB
+	case StorageProviderWebDAV:
+		return StorageBackendWebDAV
+	default:
+		return StorageBackendS3
+	}
+}
+
 func cleanObjectKey(key string) string {
 	return strings.TrimPrefix(filepath.ToSlash(filepath.Clean(strings.TrimPrefix(key, "/"))), "./")
 }