Add MVP native desktop app launcher

[deepfates]

Summary

• add a Tkinter-based native desktop shell for running Memery without the browser UI
• expose a memery-native entrypoint for easy launching of the desktop shell
• document how to run the native app alongside existing usage instructions

Testing

• not run (not requested)

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Codex Task

[deepfates]

Closing after re-evaluating against current Memery. This adds a second, untested Tkinter frontend that only lists file paths and duplicates the existing image browser without improving the retrieval or handoff story. The current product is better served by tightening the working browser UI.