style: aplicar fixes de clang-tidy (todo excepto uppercase-literal-suffix)

Corregidos ~2570 issues automáticamente con clang-tidy --fix-errors
más ajustes manuales posteriores:

- modernize: designated-initializers, trailing-return-type, use-auto,
  avoid-c-arrays (→ std::array<>), use-ranges, use-emplace,
  deprecated-headers, use-equals-default, pass-by-value,
  return-braced-init-list, use-default-member-init
- readability: math-missing-parentheses, implicit-bool-conversion,
  braces-around-statements, isolate-declaration, use-std-min-max,
  identifier-naming, else-after-return, redundant-casting,
  convert-member-functions-to-static, make-member-function-const,
  static-accessed-through-instance
- performance: avoid-endl, unnecessary-value-param, type-promotion,
  inefficient-vector-operation
- dead code: XOR_KEY (orphan tras eliminar encryptData/decryptData),
  dead stores en engine.cpp y png_shape.cpp
- NOLINT justificado en 10 funciones con alta complejidad cognitiva
  (initialize, render, main, processEvents, update×3, performDemoAction,
  randomizeOnDemoStart, renderDebugHUD, AppLogo::update)

Compilación: gcc -Wall sin warnings. clang-tidy: 0 issues.

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

source/shapes/helix_shape.cpp

@@ -1,7 +1,9 @@
 #include "helix_shape.hpp"
-#include "defines.hpp"
+
 #include <cmath>
 
+#include "defines.hpp"
+
 void HelixShape::generatePoints(int num_points, float screen_width, float screen_height) {
     num_points_ = num_points;
     radius_ = screen_height * HELIX_RADIUS_FACTOR;
@@ -41,8 +43,8 @@ void HelixShape::getPoint3D(int index, float& x, float& y, float& z) const {
     // Aplicar rotación en eje Y (horizontal)
     float cos_y = cosf(angle_y_);
     float sin_y = sinf(angle_y_);
-    float x_rot = x_base * cos_y - z_base * sin_y;
-    float z_rot = x_base * sin_y + z_base * cos_y;
+    float x_rot = (x_base * cos_y) - (z_base * sin_y);
+    float z_rot = (x_base * sin_y) + (z_base * cos_y);
 
     // Retornar coordenadas finales
     x = x_rot;
@@ -50,7 +52,7 @@ void HelixShape::getPoint3D(int index, float& x, float& y, float& z) const {
     z = z_rot;
 }
 
-float HelixShape::getScaleFactor(float screen_height) const {
+auto HelixShape::getScaleFactor(float screen_height) const -> float {
     // Factor de escala para física: proporcional a la dimensión mayor (altura total)
     // Altura base = 180px para 3 vueltas con pitch=0.25 en 240px de altura (180 = 240 * 0.25 * 3)
     const float BASE_HEIGHT = 180.0f;