Enable hiding lyrics when sharing a song

Summary
Add an option for the song owner to hide the lyrics on the public share page, so listeners can play the song without seeing the lyrics text.

Problem / user need
Users currently can't control whether lyrics are visible when they share a song. Some want to keep lyrics private (unreleased or personal songs, lyrics they plan to publish elsewhere, or a cleaner player view). Lyrics are currently always shown on shared songs.

Proposed solution

• Add a "Show lyrics" toggle in the share settings or share dialog for each song.

• When off, the shared page shows the player, title, and cover art only, with no lyrics text.

• The owner always sees their own lyrics in their library, regardless of the toggle.