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/hud_plugin.rs

@@ -2404,7 +2404,10 @@ fn update_selection_hud(
 /// When the slot has a claimed suit (any card has landed) the announcement is
 /// "▶ {Suit} Foundation"; while the slot is empty it falls back to a
 /// "▶ Foundation N" placeholder labelled by the 1-based slot index.
-fn foundation_selection_label(slot: Foundation, game: &solitaire_core::game_state::GameState) -> String {
+fn foundation_selection_label(
+    slot: Foundation,
+    game: &solitaire_core::game_state::GameState,
+) -> String {
     let claimed = game
         .pile(KlondikePile::Foundation(slot))
         .first()