feat: add --options flag to list available track lists

[NahomWondimu]

This PR adds a new --options CLI flag that lists all available track lists without starting the player.

When invoked, the flag:

• Displays the embedded chillhop list
• Discovers and lists user-provided track lists from the data directory
• Excludes internal files such as volume.txt and bookmarks.txt
• Exits cleanly without initializing audio, UI, or playback
  This change is non-invasive and does not alter existing playback behavior or defaults.

Testing
cargo run -- --options

[talwat]

They're text files, why is this better as opposed to just ls ~/.local/share/lowfi? Seems redundant.

Also, there are some strange choices, like using eyre::Ok. Could you explain those?

[NahomWondimu]

The intent was to expose available track lists from lowfi’s perspective, including the embedded list and excluding internal files, without requiring users to locate the data directory manually. If that’s out of scope, I’m happy to drop or rethink it.

The eyre::Ok import was a mistake and has been removed, thanks for catching that.