chore: cargo fmt across workspace; add analytics domain to CSP

- Apply cargo fmt to solitaire_engine, solitaire_server formatting.
- solitaire_server/src/lib.rs: add https://analytics.aleshym.co to
  script-src, img-src, and connect-src so the analytics beacon loads
  without a CSP violation.
- docs and README updates.

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

solitaire_engine/src/replay_overlay/format.rs

@@ -97,7 +97,11 @@ pub(crate) fn format_move_body(m: &ReplayMove) -> String {
     match m {
         ReplayMove::StockClick => "stock cycle".to_string(),
         ReplayMove::Move { from, to, .. } => {
-            format!("{} \u{2192} {}", format_saved_pile(from), format_saved_pile(to))
+            format!(
+                "{} \u{2192} {}",
+                format_saved_pile(from),
+                format_saved_pile(to)
+            )
         }
     }
 }