refactor: idiomatic cleanup across the codebase

Net -311 lines (1075 → 764). Build clean, clippy clean, 8 tests pass,
headless render verified.

Highlights:
- player.rs: bug fix in handle_captured_player — was cloning captured.timer
  and ticking the clone, never the real timer. Consolidated kill_player as
  pub(crate) helper (was duplicated across 3 sites). Switched from ParamSet
  to two disjoint Queries.
- enemy.rs: extracted step_attacker(), spawn_beam_visual(), end_beam(),
  pick_pattern() helpers — move_enemies is no longer 3-deep nested matches,
  beam cleanup no longer duplicated. Fixed SwoopDive overshoot check (was
  using already-applied movement). Mid-file `use` hoisted to top.
- resources.rs: added StageConfigurations::for_stage() helper (was repeated
  4×); FormationState/Score/CurrentStage now Default; extracted
  circle_formation() helper.
- stage.rs: replaced raw world: &mut World access with ordinary ResMut
  system params (no need — resource types are disjoint).
- game_state.rs: cleanup queries collapsed via Or<…> filters; dropped dead
  RestartMessage cleanup from cleanup_game_entities; button colors
  extracted as constants.
- bullet.rs: reuses kill_player; introduced GRUNT_POINTS/BOSS_POINTS with
  TODO referencing GAL-27.
- lib.rs: init_resource::<T>() for Default-implementing resources.
- Removed unused TRACTOR_BEAM_COLOR constant.
- Replaced per-frame println! debug spam with targeted info!/warn!.
- Stripped noise comments that restated what the code does.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/constants.rs

@@ -1,60 +1,61 @@
 use bevy::math::Vec2;
 use bevy::prelude::*;
 
-// --- Constants ---
+// Window
 pub const WINDOW_WIDTH: f32 = 600.0;
 pub const WINDOW_HEIGHT: f32 = 800.0;
+
+// Player
 pub const PLAYER_SPEED: f32 = 300.0;
-pub const BULLET_SPEED: f32 = 500.0;
-pub const ENEMY_SPEED: f32 = 100.0;
 pub const PLAYER_SIZE: Vec2 = Vec2::new(30.0, 30.0);
+pub const STARTING_LIVES: u32 = 3;
+pub const PLAYER_RESPAWN_DELAY: f32 = 2.0;
+pub const PLAYER_INVINCIBILITY_DURATION: f32 = 2.0;
+
+// Enemies
+pub const ENEMY_SPEED: f32 = 100.0;
 pub const ENEMY_SIZE: Vec2 = Vec2::new(40.0, 40.0);
-pub const BULLET_SIZE: Vec2 = Vec2::new(5.0, 15.0);
-// Player bullet
-pub const ENEMY_BULLET_SIZE: Vec2 = Vec2::new(8.0, 8.0);
-// Enemy bullet
-pub const ENEMY_BULLET_SPEED: f32 = 300.0;
 pub const ENEMY_SHOOT_INTERVAL: f32 = 1.5;
-// Formation constants
+
+// Bullets
+pub const BULLET_SPEED: f32 = 500.0;
+pub const BULLET_SIZE: Vec2 = Vec2::new(5.0, 15.0);
+pub const ENEMY_BULLET_SIZE: Vec2 = Vec2::new(8.0, 8.0);
+pub const ENEMY_BULLET_SPEED: f32 = 300.0;
+
+// Formation
 const FORMATION_ROWS: usize = 4;
 pub const FORMATION_COLS: usize = 8;
 pub const FORMATION_ENEMY_COUNT: usize = FORMATION_ROWS * FORMATION_COLS;
 pub const FORMATION_X_SPACING: f32 = 60.0;
 pub const FORMATION_Y_SPACING: f32 = 50.0;
 pub const FORMATION_BASE_Y: f32 = WINDOW_HEIGHT / 2.0 - 150.0;
-// Top area for formation
-pub const STARTING_LIVES: u32 = 3;
-pub const PLAYER_RESPAWN_DELAY: f32 = 2.0;
-pub const PLAYER_INVINCIBILITY_DURATION: f32 = 2.0;
-// Collision thresholds
+
+// Collision thresholds (mean of half-widths)
 pub const BULLET_ENEMY_COLLISION_THRESHOLD: f32 = (BULLET_SIZE.x + ENEMY_SIZE.x) * 0.5;
-// 22.5
 pub const PLAYER_ENEMY_COLLISION_THRESHOLD: f32 = (PLAYER_SIZE.x + ENEMY_SIZE.x) * 0.5;
-// 35.0
 pub const ENEMY_BULLET_PLAYER_COLLISION_THRESHOLD: f32 =
     (ENEMY_BULLET_SIZE.x + PLAYER_SIZE.x) * 0.5;
 
-// Tractor beam constants
+// Tractor beam
 pub const TRACTOR_BEAM_WIDTH: f32 = 20.0;
 pub const TRACTOR_BEAM_DURATION: f32 = 3.0;
-pub const TRACTOR_BEAM_COLOR: Color = Color::srgba(0.5, 0.0, 0.8, 0.6);
-pub const CAPTURE_DURATION: f32 = 10.0; // How long the player stays captured
-// Tractor beam visual constants
+pub const CAPTURE_DURATION: f32 = 10.0;
 pub const BEAM_GLOW_WIDTH: f32 = 40.0;
 pub const BEAM_GLOW_COLOR: Color = Color::srgba(0.3, 0.0, 0.5, 0.25);
 pub const BEAM_CORE_COLOR: Color = Color::srgba(0.7, 0.2, 1.0, 0.7);
 pub const BEAM_PULSE_FREQ: f32 = 3.0;
 pub const BEAM_PULSE_AMPLITUDE: f32 = 0.15;
 
-// Starfield constants
+// Starfield
 pub const STAR_COUNT: usize = 150;
 pub const STAR_MIN_SIZE: f32 = 1.0;
 pub const STAR_MAX_SIZE: f32 = 3.0;
 pub const STAR_MIN_SPEED: f32 = 20.0;
 pub const STAR_MAX_SPEED: f32 = 100.0;
-pub const STAR_Z_DEPTH: f32 = -10.0; // Behind all game entities
+pub const STAR_Z_DEPTH: f32 = -10.0;
 
-// Explosion constants
+// Explosion
 pub const EXPLOSION_DURATION: f32 = 0.4;
 pub const EXPLOSION_BASE_SIZE: Vec2 = Vec2::new(15.0, 15.0);
 pub const EXPLOSION_MAX_SIZE: Vec2 = Vec2::new(50.0, 50.0);