core: the four test literals that have failed three releases

alt_env_keys was added to ModelProviderInfo so a sandbox run can present a
machine credential instead of a human session. Three construction sites were
updated. These four are in TEST targets, and `cargo check` does not compile
those — so it printed nothing, I read nothing as clean, and every release since
has died in preflight on E0063.

A check that cannot see test targets cannot clear a change to a public struct:
literals must name every field, so ADDING one breaks every construction in the
workspace, including those only `cargo test --no-run` compiles.

Vec::new() rather than a Default on the struct — a #[serde(default)] field still
has to be written in a literal, and a Default would let the next new field land
silently in tests that should have been made to state it.

code-rs/core/tests/remote_models_manager.rs

@@ -44,7 +44,9 @@ fn remote_model(slug: &str, display: &str, priority: i32) -> ModelInfo {
 }
 
 fn provider_for(base_url: String) -> ModelProviderInfo {
+    alt_env_keys: Vec::new(),
     ModelProviderInfo {
+        alt_env_keys: Vec::new(),
         name: "mock".into(),
         base_url: Some(base_url),
         env_key: None,

code-rs/core/tests/repeated_tool_loop.rs

@@ -120,6 +120,7 @@ async fn repeated_identical_tool_cycle_stops_with_visible_error() {
     config.approval_policy = AskForApproval::Never;
     config.sandbox_policy = SandboxPolicy::DangerFullAccess;
     config.model_provider = ModelProviderInfo {
+        alt_env_keys: Vec::new(),
         base_url: Some(format!("{}/v1", server.uri())),
         ..built_in_model_providers(None)["openai"].clone()
     };

code-rs/core/tests/tool_hooks.rs

@@ -78,6 +78,7 @@ fn configure_test(
     config.sandbox_policy = SandboxPolicy::DangerFullAccess;
     config.project_hooks = ProjectHooks::from_configs(&hook_configs, &config.cwd);
     config.model_provider = ModelProviderInfo {
+        alt_env_keys: Vec::new(),
         base_url: Some(format!("{}/v1", server.uri())),
         ..built_in_model_providers(None)["openai"].clone()
     };

code-rs/core/tests/tool_selection.rs

@@ -48,6 +48,7 @@ async fn collect_tool_identifiers_for_model(model: &str) -> Vec<String> {
     let resp_mock = mount_sse_once(&server, sse).await;
 
     let model_provider = ModelProviderInfo {
+        alt_env_keys: Vec::new(),
         base_url: Some(format!("{}/v1", server.uri())),
         ..built_in_model_providers(None)["openai"].clone()
     };