feat: add test_load and test_parse binaries for configuration loading and parsing

apps/interfaces/api/src/handlers/chat.rs

@@ -112,18 +112,21 @@ pub async fn chat_completions_handler(
     // When the requested model matches the shared client we reuse it to
     // avoid allocating a new HTTP connection.  Otherwise we create a
     // temporary LlmClient with the requested model — the ownership
-    // lives on the stack via `temp_client`.
-    #[allow(unused_assignments)]
-    let mut temp_client: Option<zesdex_infrastructure::llm::LlmClient> = None;
+    // lives on the stack via a match binding.
+    //
+    // We use an uninitialized let-binding for `temp_client` so the
+    // compiler can see it's assigned at most once, avoiding
+    // `#[allow(unused_assignments)]`.
+    let temp_client;
     let llm_client = if model == state.llm_client.model {
         &state.llm_client
     } else {
-        temp_client = Some(zesdex_infrastructure::llm::LlmClient::new(
+        temp_client = zesdex_infrastructure::llm::LlmClient::new(
             state.llm_client.api_key.clone(),
             model,
             Some(state.llm_client.base_url.clone()),
-        ));
-        temp_client.as_ref().unwrap()
+        );
+        &temp_client
     };
 
     let (response, usage) = llm_client