Fix inconsistent displayed name (#13645)

* Add get_json_string_field helper

Introduce get_json_string_field in OrcaCloudServiceAgent.cpp to safely extract string fields from JSON objects.

* Add resolve_display_name helper

Introduce resolve_display_name to normalize provider metadata labels for the UI. The helper returns the first non-empty value from display_name, nickname, full_name, name, falling back to username, resolving human-facing label across varying provider payloads.

* Replace safe_str anonymous function

Replace get_json_string_field for better readability.

* Replace resolution flow for nickname with function

Consolidate both flows into one function for easier maintenance and more consistency.

* Update OrcaCloudServiceAgent.hpp

* Add OrcaCloudServiceAgent display name tests

Add unit tests verifying OrcaCloudServiceAgent resolves a user's display name from various session JSON shapes.

tests/slic3rutils/slic3rutils_tests_main.cpp

@@ -1,6 +1,47 @@
 #include <catch2/catch_all.hpp>
 
 #include "slic3r/Utils/Http.hpp"
+#include "slic3r/Utils/OrcaCloudServiceAgent.hpp"
+
+#include <wx/init.h>
+
+namespace {
+
+struct WxFixture {
+    WxFixture() { REQUIRE(initializer.IsOk()); }
+
+    wxInitializer initializer;
+};
+
+nlohmann::json flat_session_json(const nlohmann::json& fields)
+{
+    nlohmann::json session = {
+        {"access_token", "test-token"},
+        {"user_id", "test-user-id"}
+    };
+    session.update(fields);
+    return session;
+}
+
+nlohmann::json nested_session_json(const nlohmann::json& metadata)
+{
+    return {
+        {"access_token", "test-token"},
+        {"user", {
+            {"id", "test-user-id"},
+            {"user_metadata", metadata}
+        }}
+    };
+}
+
+std::string resolved_display_name(const nlohmann::json& session)
+{
+    Slic3r::OrcaCloudServiceAgent agent("");
+    REQUIRE(agent.set_user_session(session, false));
+    return agent.get_user_nickname();
+}
+
+} // namespace
 
 TEST_CASE("Check SSL certificates paths", "[Http][NotWorking]") {
     
@@ -20,6 +61,62 @@ TEST_CASE("Check SSL certificates paths", "[Http][NotWorking]") {
     REQUIRE(status == 200);
 }
 
+TEST_CASE_METHOD(WxFixture, "Orca cloud flat session resolves display name consistently", "[OrcaCloudServiceAgent]")
+{
+    CHECK(resolved_display_name(flat_session_json({
+        {"username", "orca_username"},
+        {"display_name", "Display Name"},
+        {"nickname", "Nickname"}
+    })) == "Display Name");
+
+    CHECK(resolved_display_name(flat_session_json({
+        {"username", "orca_username"},
+        {"nickname", "Nickname"}
+    })) == "Nickname");
+
+    CHECK(resolved_display_name(flat_session_json({
+        {"username", "orca_username"},
+        {"full_name", "Full Name"}
+    })) == "Full Name");
+
+    CHECK(resolved_display_name(flat_session_json({
+        {"username", "orca_username"},
+        {"name", "Provider Name"}
+    })) == "Provider Name");
+
+    CHECK(resolved_display_name(flat_session_json({
+        {"username", "orca_username"}
+    })) == "orca_username");
+}
+
+TEST_CASE_METHOD(WxFixture, "Orca cloud nested session resolves display name consistently", "[OrcaCloudServiceAgent]")
+{
+    CHECK(resolved_display_name(nested_session_json({
+        {"username", "orca_username"},
+        {"display_name", "Display Name"},
+        {"nickname", "Nickname"}
+    })) == "Display Name");
+
+    CHECK(resolved_display_name(nested_session_json({
+        {"username", "orca_username"},
+        {"nickname", "Nickname"}
+    })) == "Nickname");
+
+    CHECK(resolved_display_name(nested_session_json({
+        {"username", "orca_username"},
+        {"full_name", "Full Name"}
+    })) == "Full Name");
+
+    CHECK(resolved_display_name(nested_session_json({
+        {"username", "orca_username"},
+        {"name", "Provider Name"}
+    })) == "Provider Name");
+
+    CHECK(resolved_display_name(nested_session_json({
+        {"username", "orca_username"}
+    })) == "orca_username");
+}
+
 TEST_CASE("Http digest authentication", "[Http][NotWorking]") {
     Slic3r::Http g = Slic3r::Http::get("https://httpbingo.org/digest-auth/auth/guest/guest");