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/selection_plugin.rs

@@ -202,7 +202,10 @@ fn cycled_piles() -> Vec<KlondikePile> {
 ///
 /// If `current` is `None` the first available pile is returned.
 /// If `available` is empty, `None` is returned.
-pub fn cycle_next_pile(available: &[KlondikePile], current: Option<&KlondikePile>) -> Option<KlondikePile> {
+pub fn cycle_next_pile(
+    available: &[KlondikePile],
+    current: Option<&KlondikePile>,
+) -> Option<KlondikePile> {
     if available.is_empty() {
         return None;
     }
@@ -235,7 +238,11 @@ pub fn cycle_next_pile(available: &[KlondikePile], current: Option<&KlondikePile
 ///
 /// Both `current` and `next` must be `Some`; if either is `None` this returns
 /// `false`.
-fn did_wrap(available: &[KlondikePile], current: Option<&KlondikePile>, next: Option<&KlondikePile>) -> bool {
+fn did_wrap(
+    available: &[KlondikePile],
+    current: Option<&KlondikePile>,
+    next: Option<&KlondikePile>,
+) -> bool {
     let (Some(cur), Some(nxt)) = (current, next) else {
         return false;
     };
@@ -386,9 +393,7 @@ fn handle_selection_keys(
             KlondikePile::Tableau(Tableau::Tableau7),
         ];
         all.into_iter()
-            .filter(|p| {
-                pile_cards(&game.0, p).last().is_some_and(|c| c.face_up)
-            })
+            .filter(|p| pile_cards(&game.0, p).last().is_some_and(|c| c.face_up))
             .collect()
     };
 
@@ -717,10 +722,7 @@ fn update_selection_highlight(
 
 /// Returns the top face-up card on `pile`, or `None` if the pile is
 /// empty or its top card is face-down.
-fn top_face_up_card(
-    pile: &KlondikePile,
-    game: &GameState,
-) -> Option<Card> {
+fn top_face_up_card(pile: &KlondikePile, game: &GameState) -> Option<Card> {
     pile_cards(game, pile).last().filter(|c| c.face_up).cloned()
 }
 
@@ -1162,14 +1164,17 @@ mod tests {
         // DragState must mirror the lifted cards and carry the keyboard sentinel.
         let drag = app.world().resource::<DragState>();
         assert_eq!(drag.cards, vec![100]);
-        assert_eq!(drag.origin_pile, Some(KlondikePile::Tableau(Tableau::Tableau1)));
+        assert_eq!(
+            drag.origin_pile,
+            Some(KlondikePile::Tableau(Tableau::Tableau1))
+        );
         assert_eq!(drag.active_touch_id, Some(KEYBOARD_DRAG_TOUCH_ID));
     }
 
     /// Test 3 — Arrow keys in `Lifted` cycle through *legal* destinations
     /// only (foundations and tableaus that pass `can_place_on_*`), and
     /// wrap at the end of the list.
-        /// Test 4 — Enter while `Lifted` with a destination focused fires
+    /// Test 4 — Enter while `Lifted` with a destination focused fires
     /// exactly one `MoveRequestEvent` and resets the state machine to
     /// `Idle` with `DragState` cleared.
     #[test]