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/audit/src/error.rs

@@ -21,7 +21,7 @@ pub type AuditResult<T> = Result<T, AuditError>;
 #[derive(Error, Debug)]
 pub enum AuditError {
     #[error("Configuration error: {0}")]
-    Configuration(String),
+    Configuration(String, #[source] Option<Box<dyn std::error::Error + Send + Sync>>),
 
     #[error("config not loaded")]
     ConfigNotLoaded,
@@ -35,11 +35,14 @@ pub enum AuditError {
     #[error("System already initialized")]
     AlreadyInitialized,
 
+    #[error("Storage not available: {0}")]
+    StorageNotAvailable(String),
+
     #[error("Failed to save configuration: {0}")]
-    SaveConfig(String),
+    SaveConfig(#[source] Box<dyn std::error::Error + Send + Sync>),
 
     #[error("Failed to load configuration: {0}")]
-    LoadConfig(String),
+    LoadConfig(#[source] Box<dyn std::error::Error + Send + Sync>),
 
     #[error("Serialization error: {0}")]
     Serialization(#[from] serde_json::Error),
@@ -49,7 +52,4 @@ pub enum AuditError {
 
     #[error("Join error: {0}")]
     Join(#[from] tokio::task::JoinError),
-
-    #[error("Server storage not initialized: {0}")]
-    ServerNotInitialized(String),
 }