Expose GGUF/HF model storage location in the UI (Settings → About / Models)

[Dex321x]

Since v0.9.0, GGUF models downloaded via Hugging Face land in the HF hub cache
(on Windows: C:\Users\<user>\.cache\huggingface\hub\...), but the UI still
only shows the legacy app data directory (%APPDATA%\com.pais.handy\models).
There's no link or mention of the new location anywhere, so users looking for
their downloaded models only find the old .bin files and assume the download
failed.

Suggestion:

• Show the HF cache path in Settings → About (next to App Data Directory),
  or add an "Open model folder" button per model
• Update the README's "Manual Model Installation" section, which still only
  describes the legacy folder

Handy v0.9.1, Windows 11 x64.

[cjpais]

Yeah, this definitely needs to be updated