Implement STA apartment threading for COM server

[Copilot]

COM objects were always created in MTA state regardless of [STAThread] attribute or StandardOleMarshalObject inheritance. The main thread running the class factory callbacks was never explicitly initialized for STA.

Changes

ExecutableComServer.cs

• Call CoInitializeEx(COINIT_APARTMENTTHREADED) in PreMessageLoop() before class factory registration
• Call CoUninitialize() in PostMessageLoop() for cleanup

SimpleObject.cs

• Inherit from StandardOleMarshalObject for proper cross-apartment marshaling

Program.cs

• Add [STAThread] attribute to Main()

NativeMethods.cs

• Add COM initialization constants: COINIT_APARTMENTTHREADED, S_OK, S_FALSE, RPC_E_CHANGED_MODE

Result

Objects created via SimpleObjectClassFactory.CreateInstance() now inherit STA apartment state from the main server thread:

// PreMessageLoop() now explicitly initializes STA before registration
int hResult = NativeMethods.CoInitializeEx(
    IntPtr.Zero, 
    NativeMethods.COINIT_APARTMENTTHREADED);

// Class factory callbacks execute on STA thread
// Created objects inherit STA apartment state

Clients can verify apartment state using the existing GetProcessThreadId() method combined with thread apartment state inspection tools.

Original prompt

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This section details on the original issue you should resolve

<issue_title>Run the COMServer single Apartment state (STA)?</issue_title>
<issue_description>Is there any chance to run the COM server as in STA mode?
I tried these hints found on the internet:

• add [STAThread] to the Main method
• derive SimpleObject from StandardOleMarshalObject

But the SimpleObject is always created in MTA state . The documentation says that the apartment state of the created object is overtaken from the calling thread. SimpleObject is created in the callback method SimpleObjectClassFactory,CreateInstance which is called outside of the scope of CSExeCOMServer.Program.

Does anyone have a solution?</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Run the COMServer single Apartment state (STA)? #1

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