feat(engine): shake/settle/deal animations (#54, #55, #69)

Add FeedbackAnimPlugin with three card feedback animations:
- #54 ShakeAnim: horizontal shake on MoveRejectedEvent targeting
  destination pile cards; 0.3 s damped sine wave
- #55 SettleAnim: Y-scale bounce on valid placement (StateChangedEvent);
  1.0 → 0.92 → 1.0 over 0.15 s for all top-of-pile cards
- #69 Deal animation: slides each card from stock position to its deal
  position on NewGameRequestEvent (move_count == 0), using existing
  CardAnim with 0.04 s per-card stagger

Pure-function helpers shake_offset, settle_scale, and deal_stagger_delay
are public and covered by 6 unit tests. Fix pre-existing compile/clippy
errors: stubbed handle_confirm_input/handle_game_over_input, removed dead
CycleCardBack/CycleBackground variants, annotated ambient_handle field,
and fixed draw_mode.clone() in pause_plugin.

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

solitaire_app/src/main.rs

@@ -2,9 +2,10 @@ use bevy::prelude::*;
 use solitaire_data::{load_settings_from, provider_for_backend, settings_file_path, Settings};
 use solitaire_engine::{
     AchievementPlugin, AnimationPlugin, AudioPlugin, AutoCompletePlugin, CardPlugin,
-    ChallengePlugin, CursorPlugin, DailyChallengePlugin, GamePlugin, HelpPlugin, HudPlugin,
-    InputPlugin, LeaderboardPlugin, OnboardingPlugin, PausePlugin, ProgressPlugin, SettingsPlugin,
-    StatsPlugin, SyncPlugin, TablePlugin, TimeAttackPlugin, WeeklyGoalsPlugin,
+    ChallengePlugin, CursorPlugin, DailyChallengePlugin, FeedbackAnimPlugin, GamePlugin,
+    HelpPlugin, HudPlugin, InputPlugin, LeaderboardPlugin, OnboardingPlugin, PausePlugin,
+    ProgressPlugin, SettingsPlugin, StatsPlugin, SyncPlugin, TablePlugin, TimeAttackPlugin,
+    WeeklyGoalsPlugin,
 };
 
 fn main() {
@@ -32,6 +33,7 @@ fn main() {
         .add_plugins(CursorPlugin)
         .add_plugins(InputPlugin)
         .add_plugins(AnimationPlugin)
+        .add_plugins(FeedbackAnimPlugin)
         .add_plugins(AutoCompletePlugin)
         .add_plugins(StatsPlugin::default())
         .add_plugins(ProgressPlugin::default())