chore(workspace): fix all clippy warnings in test code

Resolves 15 violations found by `cargo clippy --workspace --tests -D warnings`:
- Remove unused imports (Card, Rank) in cursor_plugin tests
- Replace absurd i32::MAX comparison with a meaningful >= 0 check
- Use range .contains() instead of manual >= && <= (manual_range_contains)
- Move impl FromRequestParts before test module in middleware.rs (items_after_test_module)
- Move _VEC3_REFERENCED const before test module in input_plugin.rs
- Convert runtime assert on constant to const { assert!(...) }
- Use .contains() instead of .iter().any() for slice membership
- Replace .get(...).is_none() with !.contains_key(...) in HashMap checks
- Collapse Default::default() + field assignment into struct literal initializers
  across solitaire_sync, solitaire_data, and solitaire_engine test helpers

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

solitaire_engine/src/weekly_goals_plugin.rs

@@ -158,7 +158,7 @@ mod tests {
         assert_eq!(p.weekly_goal_progress.get("weekly_5_wins"), Some(&1));
         // No-undo + slow win → no_undo goal also ticked, fast goal NOT ticked.
         assert_eq!(p.weekly_goal_progress.get("weekly_3_no_undo"), Some(&1));
-        assert!(p.weekly_goal_progress.get("weekly_3_fast").is_none());
+        assert!(!p.weekly_goal_progress.contains_key("weekly_3_fast"));
     }
 
     #[test]
@@ -188,7 +188,7 @@ mod tests {
         app.update();
         let p = &app.world().resource::<ProgressResource>().0;
         assert_eq!(p.weekly_goal_progress.get("weekly_5_wins"), Some(&1));
-        assert!(p.weekly_goal_progress.get("weekly_3_no_undo").is_none());
+        assert!(!p.weekly_goal_progress.contains_key("weekly_3_no_undo"));
     }
 
     #[test]