millorat el spawn d'enemics: perimetre de seguretat i animació amb invulnerabilitat

source/core/defaults.hpp

@@ -228,5 +228,21 @@ constexpr float ROTACIO_ACCEL_DURACIO_MAX = 8.0f;     // Max transition time
 constexpr float ROTACIO_ACCEL_MULTIPLIER_MIN = 0.5f;  // Min speed multiplier
 constexpr float ROTACIO_ACCEL_MULTIPLIER_MAX = 2.5f;  // Max speed multiplier
 }  // namespace Animation
+
+// Spawn safety and invulnerability system
+namespace Spawn {
+    // Safe spawn distance from player
+    constexpr float SAFETY_DISTANCE_MULTIPLIER = 3.0f;  // 3x ship radius
+    constexpr float SAFETY_DISTANCE = Defaults::Entities::SHIP_RADIUS * SAFETY_DISTANCE_MULTIPLIER;  // 36.0f px
+    constexpr int MAX_SPAWN_ATTEMPTS = 50;  // Max attempts to find safe position
+
+    // Invulnerability system
+    constexpr float INVULNERABILITY_DURATION = 3.0f;  // Seconds
+    constexpr float INVULNERABILITY_BRIGHTNESS_START = 0.3f;  // Dim
+    constexpr float INVULNERABILITY_BRIGHTNESS_END = 0.7f;    // Normal (same as Defaults::Brightness::ENEMIC)
+    constexpr float INVULNERABILITY_SCALE_START = 0.0f;       // Invisible
+    constexpr float INVULNERABILITY_SCALE_END = 1.0f;         // Full size
+}  // namespace Spawn
+
 }  // namespace Enemies
 }  // namespace Defaults