Zoomit: Fix a issue that after trim, the video can't be saved and we can't start a new recording session (#46034)

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## Summary of the Pull Request

The bug was caused by a resource lifetime issue between the recording
phase and the save/trim phase. After a recording stopped,
StartRecordingAsync moved directly into the save workflow while it was
still holding the temporary recording stream and the active recording
session objects, later file operations in the save flow could fail
against that same file. Once that happened, ZoomIt could end up stuck in
a bad state where the first save did not complete cleanly and subsequent
recording attempts would no longer start until ZoomIt was restarted.



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## PR Checklist
As title
- [ ] Closes: #46006
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## Detailed Description of the Pull Request / Additional comments

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## Validation Steps Performed
Validated locally recording works fine when trimmed

src/modules/ZoomIt/ZoomIt/Zoomit.cpp

@@ -5679,6 +5679,16 @@ winrt::fire_and_forget StartRecordingAsync( HWND hWnd, LPRECT rcCrop, HWND hWndR
     // Recording completed (closed via hotkey or item close). Proceed to save/trim workflow.
     OutputDebugStringW(L"[Recording] StartAsync completed, entering save workflow\n");
 
+    // Release the writer stream and session objects before trim/save. Keeping the temp file
+    // open here can cause trimming and later MoveAndReplaceAsync calls to fail on the same file.
+    if (stream)
+    {
+        stream.Close();
+        stream = nullptr;
+    }
+    g_RecordingSession = nullptr;
+    g_GifRecordingSession = nullptr;
+
     // Resume on the UI thread for the save dialog
     co_await uiThread;
     OutputDebugStringW(L"[Recording] Resumed on UI thread\n");