refactor(editor): reorganize includes and enhance EditorManager initialization

- Moved the declaration of `AgentControlServer` to a forward declaration in the header file for better clarity and organization.
- Updated the `EditorManager` constructor to initialize the version string and popup manager context.
- Added conditional compilation for gRPC-related includes and commented out the agent control server initialization for future reference.
- Ensured consistent definition of `IMGUI_DEFINE_MATH_OPERATORS` across multiple files to prevent potential issues with ImGui usage.

Benefits:
- Improved code organization and readability.
- Enhanced maintainability by clarifying the initialization process and managing includes effectively.

src/app/platform/app_delegate.mm

@@ -1,4 +1,10 @@
 // AppDelegate.mm
+
+// Must define before any ImGui includes (needed by imgui_test_engine via editor_manager.h)
+#ifndef IMGUI_DEFINE_MATH_OPERATORS
+#define IMGUI_DEFINE_MATH_OPERATORS
+#endif
+
 #import "app/platform/app_delegate.h"
 #import "app/core/controller.h"
 #import "util/file_util.h"