Expose the desktopCapturer module in the main process

Editor assessment

The subject precisely states the feature: the desktopCapturer module is now exposed in the main process. The module, the process where it becomes available, and the implication (screen capture can be orchestrated without a renderer round-trip) are all clear from the header, so no body is required. The feat type is right, no scope is attached even though desktopCapturer would fit, and no footers appear. Hygiene is clean, with imperative phrasing and no trailing period. A focused, self-explanatory feature message that a reader can evaluate without any diff inspection.