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_playback.rs

@@ -268,11 +268,12 @@ pub fn step_replay_playback(
     }
     match &replay.moves[*cursor] {
         ReplayMove::Move { from, to, count } => {
-            let (Ok(from), Ok(to)) = (
-                KlondikePile::try_from(*from),
-                KlondikePile::try_from(*to),
-            ) else {
-                warn!("skipping replay move with invalid pile encoding at cursor {}", *cursor);
+            let (Ok(from), Ok(to)) = (KlondikePile::try_from(*from), KlondikePile::try_from(*to))
+            else {
+                warn!(
+                    "skipping replay move with invalid pile encoding at cursor {}",
+                    *cursor
+                );
                 *cursor += 1;
                 return false;
             };
@@ -379,10 +380,9 @@ fn tick_replay_playback(
             while *secs_to_next <= 0.0 && *cursor < replay.moves.len() {
                 match &replay.moves[*cursor] {
                     ReplayMove::Move { from, to, count } => {
-                        if let (Ok(from), Ok(to)) = (
-                            KlondikePile::try_from(*from),
-                            KlondikePile::try_from(*to),
-                        ) {
+                        if let (Ok(from), Ok(to)) =
+                            (KlondikePile::try_from(*from), KlondikePile::try_from(*to))
+                        {
                             moves_writer.write(MoveRequestEvent {
                                 from,
                                 to,