Refactor error handling in IAM and CMS crates

- Introduced `RepositoryError` and `ServiceError` enums in both IAM and CMS domains for better error management.
- Updated domain traits and services to return specific error types instead of `anyhow::Result`.
- Enhanced session and OAuth repository implementations to handle errors more explicitly.
- Refactored session service methods to return `Result<T, ServiceError>` for improved error handling.
- Updated HTTP handlers to utilize the new error types.
- Modified password hashing functions to run in a blocking context using `tokio::task::spawn_blocking`.
- Added tests for new error handling mechanisms and async password functions.

crates/zesdex-cms/src/application/conversation_service.rs

@@ -12,10 +12,10 @@
 
 use std::path::PathBuf;
 
-use anyhow::{Context, Result};
 use tracing;
 
 use crate::domain::conversation::{ChatMessage, Conversation};
+use crate::domain::error::ServiceError;
 use crate::domain::repository::ConversationRepository;
 use crate::domain::service::ConversationService;
 
@@ -59,25 +59,27 @@ impl<R: ConversationRepository> ConversationService for ConversationServiceImpl<
     /// Load a conversation from disk for the given session.
     ///
     /// Flow: resolve session dir → delegate to repo.load() → wrap error with context.
-    fn load_conversation(&self, session_id: &str) -> Result<Conversation> {
+    fn load_conversation(&self, session_id: &str) -> Result<Conversation, ServiceError> {
         tracing::debug!("loading conversation for session {session_id}");
         let dir = self.session_dir(session_id);
-        self.repo
-            .load(&dir)
-            .with_context(|| format!("failed to load conversation for session '{session_id}'"))
+        self.repo.load(&dir).map_err(|e| {
+            ServiceError::Other(format!(
+                "failed to load conversation for session '{session_id}': {e}"
+            ))
+        })
     }
 
     /// Persist a conversation to disk.
     ///
     /// Flow: resolve session dir from conv.session_id → delegate to repo.save() → wrap error.
-    fn save_conversation(&self, conv: &Conversation) -> Result<()> {
+    fn save_conversation(&self, conv: &Conversation) -> Result<(), ServiceError> {
         tracing::debug!("saving conversation for session {}", conv.session_id);
         let dir = self.session_dir(&conv.session_id);
-        self.repo.save(&dir, conv).with_context(|| {
-            format!(
-                "failed to save conversation for session '{}'",
+        self.repo.save(&dir, conv).map_err(|e| {
+            ServiceError::Other(format!(
+                "failed to save conversation for session '{}': {e}",
                 conv.session_id
-            )
+            ))
         })
     }
 
@@ -88,15 +90,15 @@ impl<R: ConversationRepository> ConversationService for ConversationServiceImpl<
     /// ## Note
     /// This is a write-through operation: the message is appended to the
     /// in-memory `Conversation` and then the full conversation is persisted.
-    fn add_message(&self, conv: &mut Conversation, msg: ChatMessage) -> Result<()> {
+    fn add_message(&self, conv: &mut Conversation, msg: ChatMessage) -> Result<(), ServiceError> {
         tracing::debug!("adding message to session {}", conv.session_id);
         conv.push(msg); // append message to in-memory conversation
         let dir = self.session_dir(&conv.session_id);
-        self.repo.save(&dir, conv).with_context(|| {
-            format!(
-                "failed to persist conversation after adding message for session '{}'",
+        self.repo.save(&dir, conv).map_err(|e| {
+            ServiceError::Other(format!(
+                "failed to persist conversation after adding message for session '{}': {e}",
                 conv.session_id
-            )
+            ))
         })
     }
 }