Lint: rename de métodos privados (camelBack + traducción al inglés)

Tanda grande de identifier-naming: 47 métodos privados pasan de
snake_case (en su mayoría catalán/spanish) a camelBack inglés. Solo
afecta a sus archivos hpp+cpp; ningún símbolo cruza fichero (los
públicos quedan para una pasada manual con VS Code).

Renames por clase:

- ShapeLoader: resolve_path → resolvePath.
- VectorText: load_charset → loadCharset, get_shape_filename →
  getShapeFilename.
- Shape: starts_with → startsWith (cuidado de no tocar
  std::string::starts_with que también usaba), extract_value →
  extractValue, parse_center → parseCenter, parse_points → parsePoints.
- Starfield: inicialitzar_estrella → initStar, fora_area →
  isOutsideArea, calcular_escala → computeScale, calcular_brightness →
  computeBrightness.
- TitleScene: actualitzar_animacio_logo → updateLogoAnimation,
  inicialitzar_titol → initTitle.
- LogoScene: inicialitzar_lletres → initLetters, actualitzar_explosions
  → updateExplosions, canviar_estat → changeState,
  totes_lletres_completes → allLettersComplete.
- SpawnController: generar_spawn_events → generateSpawnEvents,
  seleccionar_tipus_aleatori → selectRandomType, spawn_enemic →
  spawnEnemy, aplicar_multiplicadors → applyMultipliers.
- ShipAnimator: actualitzar_entering/floating/exiting →
  updateEntering/Floating/Exiting, configurar_nau_p1/p2 →
  configureShipP1/P2, calcular_posicio_fora_pantalla →
  computeOffscreenPosition.
- GameScene: dibuixar_marges → drawMargins, dibuixar_marcador →
  drawScoreboard, disparar_bala → fireBullet, obtenir_punt_spawn →
  getSpawnPoint, unir_jugador → joinPlayer, dibuixar_continue →
  drawContinue, dibuixar_missatge_stage → drawStageMessage.
- StageLoader: parse_metadata/stage/spawn_config/distribution/multipliers/
  spawn_mode → parseMetadata/Stage/SpawnConfig/Distribution/Multipliers/
  SpawnMode, validar_config → validateConfig.
- StageManager: canviar_estat → changeState,
  processar_init_hud/level_start/playing/level_completed →
  processInitHud/LevelStart/Playing/LevelCompleted, carregar_stage →
  loadStage.

Métodos públicos y funciones libres (cross-file) quedan a propósito sin
tocar — los renombrará el usuario con la herramienta de rename de VS Code.

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

source/core/graphics/shape.cpp

@@ -49,27 +49,27 @@ auto Shape::parseFile(const std::string& contingut) -> bool {
         }
 
         // Parse command
-        if (starts_with(line, "name:")) {
-            nom_ = trim(extract_value(line));
-        } else if (starts_with(line, "scale:")) {
+        if (startsWith(line, "name:")) {
+            nom_ = trim(extractValue(line));
+        } else if (startsWith(line, "scale:")) {
             try {
-                escala_defecte_ = std::stof(extract_value(line));
+                escala_defecte_ = std::stof(extractValue(line));
             } catch (...) {
                 std::cerr << "[Shape] Warning: scale invàlida, usant 1.0" << '\n';
                 escala_defecte_ = 1.0F;
             }
-        } else if (starts_with(line, "center:")) {
-            parse_center(extract_value(line));
-        } else if (starts_with(line, "polyline:")) {
-            auto points = parse_points(extract_value(line));
+        } else if (startsWith(line, "center:")) {
+            parseCenter(extractValue(line));
+        } else if (startsWith(line, "polyline:")) {
+            auto points = parsePoints(extractValue(line));
             if (points.size() >= 2) {
                 primitives_.push_back({PrimitiveType::POLYLINE, points});
             } else {
                 std::cerr << "[Shape] Warning: polyline con menys de 2 points ignorada"
                           << '\n';
             }
-        } else if (starts_with(line, "line:")) {
-            auto points = parse_points(extract_value(line));
+        } else if (startsWith(line, "line:")) {
+            auto points = parsePoints(extractValue(line));
             if (points.size() == 2) {
                 primitives_.push_back({PrimitiveType::LINE, points});
             } else {
@@ -100,8 +100,8 @@ auto Shape::trim(const std::string& str) const -> std::string {
     return str.substr(start, end - start + 1);
 }
 
-// Helper: starts_with
-auto Shape::starts_with(const std::string& str,
+// Helper: startsWith
+auto Shape::startsWith(const std::string& str,
     const std::string& prefix) const -> bool {
     if (str.length() < prefix.length()) {
         return false;
@@ -110,7 +110,7 @@ auto Shape::starts_with(const std::string& str,
 }
 
 // Helper: extract value after ':'
-auto Shape::extract_value(const std::string& line) const -> std::string {
+auto Shape::extractValue(const std::string& line) const -> std::string {
     size_t colon = line.find(':');
     if (colon == std::string::npos) {
         return "";
@@ -119,7 +119,7 @@ auto Shape::extract_value(const std::string& line) const -> std::string {
 }
 
 // Helper: parse center "x, y"
-void Shape::parse_center(const std::string& value) {
+void Shape::parseCenter(const std::string& value) {
     std::string val = trim(value);
     size_t comma = val.find(',');
     if (comma != std::string::npos) {
@@ -134,7 +134,7 @@ void Shape::parse_center(const std::string& value) {
 }
 
 // Helper: parse points "x1,y1  x2,y2  x3,y3"
-auto Shape::parse_points(const std::string& str) const -> std::vector<Vec2> {
+auto Shape::parsePoints(const std::string& str) const -> std::vector<Vec2> {
     std::vector<Vec2> points;
     std::istringstream iss(trim(str));
     std::string pair;