Move project save commit planning to app core

src/app_core/document_canvas.h

@@ -118,6 +118,23 @@ struct DocumentCanvasProjectSaveWritePlan {
     bool falls_back_to_direct_on_temporary_open_failure = false;
 };
 
+struct DocumentCanvasProjectSaveCommitInput {
+    bool used_temporary = false;
+    bool target_remove_attempted = false;
+    bool target_remove_succeeded = false;
+    bool temporary_rename_attempted = false;
+    bool temporary_rename_succeeded = false;
+};
+
+struct DocumentCanvasProjectSaveCommitPlan {
+    bool saved = false;
+    bool used_temporary = false;
+    bool target_removed = false;
+    bool temporary_renamed = false;
+    bool target_may_be_missing = false;
+    std::string_view log_message;
+};
+
 class DocumentCanvasClearServices {
 public:
     virtual ~DocumentCanvasClearServices() = default;
@@ -397,6 +414,36 @@ plan_document_canvas_project_save_write(
     return pp::foundation::Result<DocumentCanvasProjectSaveWritePlan>::success(std::move(plan));
 }
 
+[[nodiscard]] constexpr DocumentCanvasProjectSaveCommitPlan plan_document_canvas_project_save_commit(
+    DocumentCanvasProjectSaveCommitInput input) noexcept
+{
+    DocumentCanvasProjectSaveCommitPlan plan;
+    plan.used_temporary = input.used_temporary;
+
+    if (!input.used_temporary) {
+        plan.saved = true;
+        plan.log_message = "project saved to target";
+        return plan;
+    }
+
+    if (!input.target_remove_attempted || !input.target_remove_succeeded) {
+        plan.log_message = "could not remove target project before temporary swap";
+        return plan;
+    }
+
+    plan.target_removed = true;
+    if (!input.temporary_rename_attempted || !input.temporary_rename_succeeded) {
+        plan.target_may_be_missing = true;
+        plan.log_message = "temporary project not swapped after original removal";
+        return plan;
+    }
+
+    plan.saved = true;
+    plan.temporary_renamed = true;
+    plan.log_message = "temporary project swapped successfully";
+    return plan;
+}
+
 [[nodiscard]] inline pp::foundation::Result<DocumentCanvasClearPlan> plan_document_canvas_clear(
     bool has_canvas,
     float r = 0.0F,