chore(deps): migrate to Bevy 0.16, axum 0.8, and other package updates

- Bump bevy 0.15 → 0.16; fixes all breaking API changes:
  ChildBuilder → ChildSpawnerCommands, Parent → ChildOf,
  despawn_descendants → despawn_related::<Children>(),
  despawn_recursive → despawn (now recursive by default),
  EventWriter::send → write, Query::{get_single,get_single_mut}
  → {single,single_mut}, ChildOf::get → parent()
- Bump axum 0.7 → 0.8; remove axum::async_trait from FromRequestParts
- Bump tower_governor 0.4 → 0.8; fix GovernorLayer::new() API
- Bump jsonwebtoken 9 → 10 with rust_crypto feature only
- Bump thiserror 1 → 2, dirs 5 → 6, bcrypt 0.15 → 0.19,
  reqwest 0.12 → 0.13 (rustls feature rename)
- Regenerate .sqlx offline cache for sqlx compile-time query checks

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

solitaire_engine/src/time_attack_plugin.rs

@@ -60,7 +60,7 @@ fn handle_start_time_attack_request(
         return;
     }
     if progress.0.level < CHALLENGE_UNLOCK_LEVEL {
-        info_toast.send(InfoToastEvent(format!(
+        info_toast.write(InfoToastEvent(format!(
             "Time Attack unlocks at level {CHALLENGE_UNLOCK_LEVEL}"
         )));
         return;
@@ -70,7 +70,7 @@ fn handle_start_time_attack_request(
         remaining_secs: TIME_ATTACK_DURATION_SECS,
         wins: 0,
     };
-    new_game.send(NewGameRequestEvent {
+    new_game.write(NewGameRequestEvent {
         seed: None,
         mode: Some(GameMode::TimeAttack),
     });
@@ -93,7 +93,7 @@ fn advance_time_attack(
         let wins = session.wins;
         session.active = false;
         session.remaining_secs = 0.0;
-        ended.send(TimeAttackEndedEvent { wins });
+        ended.write(TimeAttackEndedEvent { wins });
     }
 }
 
@@ -108,7 +108,7 @@ fn auto_deal_on_time_attack_win(
             continue;
         }
         session.wins = session.wins.saturating_add(1);
-        new_game.send(NewGameRequestEvent {
+        new_game.write(NewGameRequestEvent {
             seed: None,
             mode: Some(GameMode::TimeAttack),
         });