chore: use singular style in config class name (#5489)

api/configs/app_config.py

@@ -0,0 +1,42 @@
+from pydantic_settings import BaseSettings, SettingsConfigDict
+
+from configs.deploy import DeploymentConfig
+from configs.enterprise import EnterpriseFeatureConfig
+from configs.extra import ExtraServiceConfig
+from configs.feature import FeatureConfig
+from configs.middleware import MiddlewareConfig
+from configs.packaging import PackagingInfo
+
+
+class DifyConfig(
+    # based on pydantic-settings
+    BaseSettings,
+
+    # Packaging info
+    PackagingInfo,
+
+    # Deployment configs
+    DeploymentConfig,
+
+    # Feature configs
+    FeatureConfig,
+
+    # Middleware configs
+    MiddlewareConfig,
+
+    # Extra service configs
+    ExtraServiceConfig,
+
+    # Enterprise feature configs
+    # **Before using, please contact business@dify.ai by email to inquire about licensing matters.**
+    EnterpriseFeatureConfig,
+):
+
+    model_config = SettingsConfigDict(
+        # read from dotenv format config file
+        env_file='.env',
+        env_file_encoding='utf-8',
+
+        # ignore extra attributes
+        extra='ignore',
+    )