chore: rename app from Solitaire Quest to Ferrous Solitaire

Replace all display-name occurrences across web pages, Rust source,
docs, and Cargo metadata. Update localStorage token key from sq_token
to fs_token. Tagline "Klondike Solitaire" retained as genre descriptor.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

solitaire_engine/src/lib.rs

@@ -1,4 +1,4 @@
-//! Bevy integration layer for Solitaire Quest.
+//! Bevy integration layer for Ferrous Solitaire.
 
 #[cfg(target_os = "android")]
 pub mod android_clipboard;