fix: don't spin forever on unhandled file change actions (windows) - #1152
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The Windows FileSystemWatcher walked the FILE_NOTIFY_INFORMATION list with a that skipped unknown actions without advancing to the next entry, so any notification Windows delivers outside the five handled actions (alternate data stream and file id notifications, as generated by OneDrive and similar) pinned the watcher thread in an infinite loop at 100% CPU while holding its lock. The thread then no longer reached threadShouldExit(), so shutdown fell back to TerminateThread and the process could outlive a normal quit. Skip unrecognized actions instead of looping on them, bound the buffer walk by the returned byte count, align the buffer as ReadDirectoryChangesW requires, and stop retrying a failed read in a tight loop (recovering on ERROR_NOTIFY_ENUM_DIR with a full folder refresh).
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The Windows FileSystemWatcher walked the FILE_NOTIFY_INFORMATION list with a that skipped unknown actions without advancing to the next entry, so any notification Windows delivers outside the five handled actions (alternate data stream and file id notifications, as generated by OneDrive and similar) pinned the watcher thread in an infinite loop at 100% CPU while holding its lock. The thread then no longer reached threadShouldExit(), so shutdown fell back to TerminateThread and the process could outlive a normal quit.
Skip unrecognized actions instead of looping on them, bound the buffer walk by the returned byte count, align the buffer as ReadDirectoryChangesW requires, and stop retrying a failed read in a tight loop (recovering on ERROR_NOTIFY_ENUM_DIR with a full folder refresh).