feat(engine): add daily challenge, level-up toast, and daily_devotee achievement

Phase 6 part 2 (partial):
- daily_seed_for(date) and PlayerProgress::record_daily_completion in
  solitaire_data, with streak logic that increments on consecutive days,
  resets on a skipped day, and is idempotent on same-day re-completions.
- DailyChallengePlugin tracks today's seed, awards +100 XP and updates
  the streak when the player wins a game whose seed matches. Pressing C
  starts a new game with the daily seed.
- LevelUpEvent toast in AnimationPlugin announces level changes.
- AchievementContext gains daily_challenge_streak; daily_devotee
  achievement unlocks at streak >= 7. AchievementPlugin reads
  ProgressResource and runs after ProgressUpdate.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

solitaire_app/src/main.rs

@@ -1,7 +1,7 @@
 use bevy::prelude::*;
 use solitaire_engine::{
-    AchievementPlugin, AnimationPlugin, CardPlugin, GamePlugin, InputPlugin, ProgressPlugin,
-    StatsPlugin, TablePlugin,
+    AchievementPlugin, AnimationPlugin, CardPlugin, DailyChallengePlugin, GamePlugin, InputPlugin,
+    ProgressPlugin, StatsPlugin, TablePlugin,
 };
 
 fn main() {
@@ -22,7 +22,8 @@ fn main() {
         .add_plugins(InputPlugin)
         .add_plugins(AnimationPlugin)
         .add_plugins(StatsPlugin::default())
-        .add_plugins(AchievementPlugin::default())
         .add_plugins(ProgressPlugin::default())
+        .add_plugins(AchievementPlugin::default())
+        .add_plugins(DailyChallengePlugin)
         .run();
 }