feat(provider): add google project and location fields

Add support for Google Cloud-specific configuration in provider models.
New fields `GoogleProject` and `GoogleLocation` are now included in the
Provider DTO, database model, API handlers, and sync service snapshots.

- Extend Provider struct in model with gorm/json tags
- Update ProviderDTO with omitempty JSON tags
- Include fields in handler create/update logic with trim
- Add fields to providerSnapshot for sync operations

internal/api/handler.go

@@ -58,15 +58,17 @@ func (h *Handler) CreateProvider(c *gin.Context) {
 	}
 
 	provider := model.Provider{
-		Name:      req.Name,
-		Type:      req.Type,
-		BaseURL:   req.BaseURL,
-		APIKey:    req.APIKey,
-		Group:     group,
-		Models:    strings.Join(req.Models, ","),
-		Status:    status,
-		AutoBan:   autoBan,
-		BanReason: req.BanReason,
+		Name:           req.Name,
+		Type:           req.Type,
+		BaseURL:        req.BaseURL,
+		APIKey:         req.APIKey,
+		GoogleProject:  strings.TrimSpace(req.GoogleProject),
+		GoogleLocation: strings.TrimSpace(req.GoogleLocation),
+		Group:          group,
+		Models:         strings.Join(req.Models, ","),
+		Status:         status,
+		AutoBan:        autoBan,
+		BanReason:      req.BanReason,
 	}
 	if !req.BanUntil.IsZero() {
 		tu := req.BanUntil.UTC()
@@ -133,6 +135,12 @@ func (h *Handler) UpdateProvider(c *gin.Context) {
 	if req.APIKey != "" {
 		update["api_key"] = req.APIKey
 	}
+	if strings.TrimSpace(req.GoogleProject) != "" {
+		update["google_project"] = strings.TrimSpace(req.GoogleProject)
+	}
+	if strings.TrimSpace(req.GoogleLocation) != "" {
+		update["google_location"] = strings.TrimSpace(req.GoogleLocation)
+	}
 	if req.Models != nil {
 		update["models"] = strings.Join(req.Models, ",")
 	}