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_data/src/lib.rs

@@ -48,6 +48,6 @@ pub use achievements::{
 
 pub mod progress;
 pub use progress::{
-    level_for_xp, load_progress_from, progress_file_path, save_progress_to, xp_for_win,
-    PlayerProgress,
+    daily_seed_for, level_for_xp, load_progress_from, progress_file_path, save_progress_to,
+    xp_for_win, PlayerProgress,
 };