feat(storage): refactor audit and notification with OperationHelper (#825)

* improve code for audit

* improve code ecfs.rs

* improve code

* improve code for ecfs.rs

* feat(storage): refactor audit and notification with OperationHelper

This commit introduces a significant refactoring of the audit logging and event notification mechanisms within `ecfs.rs`.

The core of this change is the new `OperationHelper` struct, which encapsulates and simplifies the logic for both concerns. It replaces the previous `AuditHelper` and manual event dispatching.

Key improvements include:

- **Unified Handling**: `OperationHelper` manages both audit and notification builders, providing a single, consistent entry point for S3 operations.
- **RAII for Automation**: By leveraging the `Drop` trait, the helper automatically dispatches logs and notifications when it goes out of scope. This simplifies S3 method implementations and ensures cleanup even on early returns.
- **Fluent API**: A builder-like pattern with methods such as `.object()`, `.version_id()`, and `.suppress_event()` makes the code more readable and expressive.
- **Context-Aware Logic**: The helper's `.complete()` method intelligently populates log details based on the operation's `S3Result` and only triggers notifications on success.
- **Modular Design**: All helper logic is now isolated in `rustfs/src/storage/helper.rs`, improving separation of concerns and making `ecfs.rs` cleaner.

This refactoring significantly enhances code clarity, reduces boilerplate, and improves the robustness of logging and notification handling across the storage layer.

* fix

* fix

* fix

* fix

* fix

* fix

* fix

* improve code for audit and notify

* fix

* fix

* fix

crates/notify/src/integration.rs

@@ -199,7 +199,9 @@ impl NotificationSystem {
         F: FnMut(&mut Config) -> bool, // The closure returns a boolean value indicating whether the configuration has been changed
     {
         let Some(store) = rustfs_ecstore::global::new_object_layer_fn() else {
-            return Err(NotificationError::ServerNotInitialized);
+            return Err(NotificationError::StorageNotAvailable(
+                "Failed to save target configuration: server storage not initialized".to_string(),
+            ));
         };
 
         let mut new_config = rustfs_ecstore::config::com::read_config_without_migrate(store.clone())