Refactor session ID handling and improve error management

- Introduced `SessionId` newtype for validated session identifiers, ensuring safety against path traversal attacks.
- Updated session repository methods to accept `SessionId` instead of raw strings, enhancing type safety.
- Removed redundant error handling in repository methods by leveraging the new `Error` type from `zesdex_utils`.
- Simplified atomic JSON write operations by eliminating unnecessary error conversions.
- Enhanced integer casting with a new `CastOr` trait for safer narrowing conversions.
- Removed deprecated error handling code and consolidated error types across the codebase.
- Updated HTTP handlers to utilize the new session ID validation, improving overall robustness.

crates/zesdex-iam/src/domain/service.rs

@@ -8,6 +8,8 @@
 //!
 //! - [`SessionService`] — create, list, archive sessions
 //! - [`OAuthService`] — start PKCE flow, complete code exchange, retrieve token
+use zesdex_entities::domain::auth::SessionId;
+
 use crate::domain::error::ServiceError;
 use crate::domain::oauth::{OAuthConfig, OAuthToken};
 use crate::domain::session::Session;
@@ -21,7 +23,7 @@ pub trait SessionService {
     fn list_all(&self) -> Result<Vec<Session>, ServiceError>;
 
     /// Archive a session by id (sets `archived = true`).
-    fn archive_session(&self, id: &str) -> Result<(), ServiceError>;
+    fn archive_session(&self, id: SessionId) -> Result<(), ServiceError>;
 }
 
 /// OAuth flow use-case boundary.