dsh-png-pet: DeepSeek Harness Desktop Pet Companion

The `dsh-png-pet` plugin for DeepSeek Harness (DSH) is a local desktop pet companion that runs on the Windows desktop. Its core features include handling questionnaires in the desktop pet interface (with draft-saving support), always-on minimal chat (with screenshot paste support), custom character avatars (GIF/PNG), and physical interactions (dragging and throwing). The plugin communicates via stdin/stdout and emphasizes privacy and security. Users need to run the installation command in PowerShell and restart DSH Harness to enable it.