Fase 8a+b: paleta semantica de color por entidad

Cada entity declara su color de linea via parametro opcional. Cuando
alpha==0 el pipeline cae al color global del oscilador (compatibilidad
con el comportamiento anterior).

Defaults::Palette (defaults.hpp):
- SHIP        = blanco neutro
- BULLET      = verde laser
- PENTAGON    = azul "esquivador"
- QUADRAT     = rojo "tank"
- MOLINILLO   = magenta agresivo

Pipeline:
- linea(): parametro SDL_Color color (default {0,0,0,0}). En .cpp,
  fuente del color = color.a>0 ? color : g_current_line_color.
- render_shape(): parametro SDL_Color color que propaga a cada linea
  del shape.
- Debris: campo color en la struct; explode() recibe SDL_Color color
  y lo guarda en cada fragment; draw() lo pasa a linea().

Aplicacion:
- Ship::draw -> Palette::SHIP.
- Bullet::draw -> Palette::BULLET.
- Enemy::draw -> Palette::{PENTAGON,QUADRAT,MOLINILLO} segun type_.
- CollisionSystem detectBulletEnemy: debris hereda color del enemy.
- GameScene::tocado: debris hereda Palette::SHIP.

Smoke test xvfb OK.

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

source/core/rendering/line_renderer.cpp

@@ -16,7 +16,8 @@ float g_current_line_thickness = 1.5F;
 void linea(Renderer* renderer,
            int x1, int y1, int x2, int y2,
            float brightness,
-           float thickness) {
+           float thickness,
+           SDL_Color color) {
     if (renderer == nullptr) {
         return;
     }
@@ -28,10 +29,11 @@ void linea(Renderer* renderer,
     const float FX2 = static_cast<float>(x2);
     const float FY2 = static_cast<float>(y2);
 
-    // Color: aplicar brightness al color oscilatorio global. Convertir 0..255 → 0..1.
-    const float R = (static_cast<float>(g_current_line_color.r) * brightness) / 255.0F;
-    const float G = (static_cast<float>(g_current_line_color.g) * brightness) / 255.0F;
-    const float B = (static_cast<float>(g_current_line_color.b) * brightness) / 255.0F;
+    // color.alpha==0 → usar global del oscilador. alpha>0 → color directo.
+    const SDL_Color SOURCE = (color.a > 0) ? color : g_current_line_color;
+    const float R = (static_cast<float>(SOURCE.r) * brightness) / 255.0F;
+    const float G = (static_cast<float>(SOURCE.g) * brightness) / 255.0F;
+    const float B = (static_cast<float>(SOURCE.b) * brightness) / 255.0F;
 
     const float W = (thickness > 0.0F) ? thickness : g_current_line_thickness;
 

source/core/rendering/line_renderer.hpp

@@ -18,10 +18,13 @@ namespace Rendering {
 // Dibuja una línea entre dos puntos en coordenadas lógicas (1280×720).
 // brightness: factor de brillo (0.0..1.0, default 1.0 = brillo máximo).
 // thickness: grosor en píxeles lógicos. Si <= 0 usa g_current_line_thickness.
+// color: si alpha==0, se usa el color global del oscilador; si alpha>0 se
+//        usa este color directo (paleta semántica por entidad).
 void linea(Renderer* renderer,
            int x1, int y1, int x2, int y2,
            float brightness = 1.0F,
-           float thickness = 0.0F);
+           float thickness = 0.0F,
+           SDL_Color color = {0, 0, 0, 0});
 
 // Color global de las líneas (lo actualiza ColorOscillator vía SDLManager).
 void setLineColor(SDL_Color color);

source/core/rendering/shape_renderer.cpp

@@ -79,40 +79,31 @@ void render_shape(Rendering::Renderer* renderer,
     float scale,
     float progress,
     float brightness,
-    const Rotation3D* rotation_3d) {
-    // Verificar que la shape es vàlida
+    const Rotation3D* rotation_3d,
+    SDL_Color color) {
     if (!shape || !shape->isValid()) {
         return;
     }
-
-    // Si progress < 1.0, no draw (tot o res)
     if (progress < 1.0F) {
         return;
     }
 
-    // Obtenir el centro de la shape para transformacions
-    const Vec2& shape_centre = shape->getCenter();
+    const Vec2& SHAPE_CENTRE = shape->getCenter();
 
-    // Iterar sobre todas las primitives
     for (const auto& primitive : shape->get_primitives()) {
         if (primitive.type == Graphics::PrimitiveType::POLYLINE) {
-            // POLYLINE: connectar points consecutius
+            // POLYLINE: conectar puntos consecutivos.
             for (size_t i = 0; i < primitive.points.size() - 1; i++) {
-                Vec2 p1 = transform_point(primitive.points[i], shape_centre, position, angle, scale, rotation_3d);
-                Vec2 p2 = transform_point(primitive.points[i + 1], shape_centre, position, angle, scale, rotation_3d);
-
-                linea(renderer, static_cast<int>(p1.x), static_cast<int>(p1.y),
-                      static_cast<int>(p2.x), static_cast<int>(p2.y), brightness);
-            }
-        } else {  // PrimitiveType::LINE
-            // LINE: exactament 2 points
-            if (primitive.points.size() >= 2) {
-                Vec2 p1 = transform_point(primitive.points[0], shape_centre, position, angle, scale, rotation_3d);
-                Vec2 p2 = transform_point(primitive.points[1], shape_centre, position, angle, scale, rotation_3d);
-
-                linea(renderer, static_cast<int>(p1.x), static_cast<int>(p1.y),
-                      static_cast<int>(p2.x), static_cast<int>(p2.y), brightness);
+                const Vec2 P1 = transform_point(primitive.points[i], SHAPE_CENTRE, position, angle, scale, rotation_3d);
+                const Vec2 P2 = transform_point(primitive.points[i + 1], SHAPE_CENTRE, position, angle, scale, rotation_3d);
+                linea(renderer, static_cast<int>(P1.x), static_cast<int>(P1.y),
+                      static_cast<int>(P2.x), static_cast<int>(P2.y), brightness, 0.0F, color);
             }
+        } else if (primitive.points.size() >= 2) {  // LINE
+            const Vec2 P1 = transform_point(primitive.points[0], SHAPE_CENTRE, position, angle, scale, rotation_3d);
+            const Vec2 P2 = transform_point(primitive.points[1], SHAPE_CENTRE, position, angle, scale, rotation_3d);
+            linea(renderer, static_cast<int>(P1.x), static_cast<int>(P1.y),
+                  static_cast<int>(P2.x), static_cast<int>(P2.y), brightness, 0.0F, color);
         }
     }
 }

source/core/rendering/shape_renderer.hpp

@@ -49,6 +49,7 @@ void render_shape(Rendering::Renderer* renderer,
     float scale = 1.0F,
     float progress = 1.0F,
     float brightness = 1.0F,
-    const Rotation3D* rotation_3d = nullptr);
+    const Rotation3D* rotation_3d = nullptr,
+    SDL_Color color = {0, 0, 0, 0});  // alpha==0 → usa global oscilador
 
 }  // namespace Rendering