feat: complete v0.3.1 agent workflow

pkg/config/config_test.go

@@ -477,3 +477,28 @@ providers:
 		t.Fatalf("responses thinking param = %q, want %q", got, "reasoning")
 	}
 }
+
+func TestLoadCustomThinkingParam(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "agentu.yaml")
+	if err := os.WriteFile(path, []byte(`
+providers:
+  custom:
+    api_type: chat
+    base_url: https://example.com
+    api_key: sk-test
+    thinking_param: reasoning_effort
+    models:
+      - id: custom-model
+        thinking: high
+`), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	cfg, err := Load(path)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got := cfg.Providers["custom"].ThinkingParam; got != "reasoning_effort" {
+		t.Fatalf("thinking param = %q", got)
+	}
+}