Refactor CMS and IAM modules: restructure presentation and command layers

- Removed HTTP adapter module from CMS infrastructure.
- Updated CMS infrastructure module to exclude HTTP.
- Introduced presentation layer in CMS with DTOs and handlers for REST API.
- Added command types for CMS domain operations to encapsulate input data.
- Created typed error handling for CMS presentation layer.
- Implemented handlers for CMS REST API endpoints.
- Removed HTTP DTOs and handlers from IAM infrastructure.
- Introduced command types for IAM domain operations.
- Created presentation layer in IAM with DTOs and handlers for OAuth flow.
- Implemented typed error handling for IAM presentation layer.

crates/zesdex-utils/src/error.rs

@@ -71,7 +71,8 @@ impl Error {
 
     /// Convert an `anyhow::Error` to `zesdex_utils::Error` by attempting
     /// downcast to known inner types.
-    pub fn from_anyhow(e: anyhow::Error) -> Self {
+    #[must_use]
+    pub fn from_anyhow(e: &anyhow::Error) -> Self {
         if let Some(ioe) = e.downcast_ref::<std::io::Error>() {
             return Error::Io(std::io::Error::new(ioe.kind(), ioe.to_string()));
         }