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/pending_hint.rs

@@ -26,8 +26,8 @@
 
 use bevy::prelude::*;
 use bevy::tasks::{AsyncComputeTaskPool, Task, futures_lite::future};
-use solitaire_core::game_state::GameState;
 use klondike::KlondikePile;
+use solitaire_core::game_state::GameState;
 use solitaire_core::solver::{SolverConfig, SolverResult, try_solve_from_state};
 
 use crate::card_plugin::CardEntity;
@@ -101,7 +101,10 @@ struct HintTask {
 enum HintTaskOutput {
     /// Solver verdict was `Winnable`; here is the first move on the
     /// solution path.
-    SolverMove { from: KlondikePile, to: KlondikePile },
+    SolverMove {
+        from: KlondikePile,
+        to: KlondikePile,
+    },
     /// Solver was `Unwinnable` or `Inconclusive`. The poll system
     /// runs the legacy heuristic against the live `GameState` so the
     /// H key always produces feedback while any legal move exists.