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_data/src/settings.rs

@@ -49,7 +49,7 @@ pub enum SyncBackend {
     #[default]
     #[serde(rename = "local")]
     Local,
-    /// Sync with a self-hosted Solitaire Quest server.
+    /// Sync with a self-hosted Ferrous Solitaire server.
     #[serde(rename = "solitaire_server")]
     SolitaireServer {
         /// Base URL of the server, e.g. `"https://solitaire.example.com"`.

solitaire_data/src/sync_client.rs

@@ -6,7 +6,7 @@
 //! | Struct | Backend |
 //! |---|---|
 //! | [`LocalOnlyProvider`] | No-op; used when sync is disabled |
-//! | [`SolitaireServerClient`] | Self-hosted Solitaire Quest server (JWT auth) |
+//! | [`SolitaireServerClient`] | Self-hosted Ferrous Solitaire server (JWT auth) |
 //!
 //! Use [`provider_for_backend`] to obtain a `Box<dyn SyncProvider + Send + Sync>`
 //! without matching on [`SyncBackend`] anywhere else in the codebase.
@@ -55,7 +55,7 @@ impl SyncProvider for LocalOnlyProvider {
 // SolitaireServerClient
 // ---------------------------------------------------------------------------
 
-/// HTTP sync client for the self-hosted Solitaire Quest server.
+/// HTTP sync client for the self-hosted Ferrous Solitaire server.
 ///
 /// Authenticates via JWT stored in the OS keychain. On a 401 response the
 /// client automatically attempts a token refresh and retries the request once