feat(logo): timeline lineal de 7 fases amb glitch tail i durades al YAML

source/core/rendering/effects/scan_reveal.cpp

@@ -50,6 +50,8 @@ namespace Effects {
         burst_remaining_ms_ = 0;
         burst_y_norm_ = 0.0F;
         burst_dx_ = 0;
+        tail_started_ = false;
+        tail_remaining_ms_ = 0;
     }
 
     void ScanReveal::tick(int delta_ms) {
@@ -63,9 +65,13 @@ namespace Effects {
             burst_remaining_ms_ = std::max(0, burst_remaining_ms_ - delta_ms);
         }
 
-        // 3) Spawn d'un nou burst (només durant el scan, no al flash).
+        // 3) Spawn d'un nou burst. Permès durant el scan i durant el
+        //    glitch tail post-flash; bloquejat exactament durant el
+        //    flash perquè aquell és un punt visual de tancament net.
         //    Probabilitat per frame ≈ (per_sec/1000) · delta_ms.
-        if (burst_remaining_ms_ == 0 && elapsed_ms_ < params_.duration_ms && params_.vhs_burst_per_sec > 0 && params_.vhs_burst_duration_ms > 0) {
+        const bool TAIL_ACTIVE = tail_started_ && tail_remaining_ms_ > 0;
+        const bool SCAN_ONGOING = elapsed_ms_ < params_.duration_ms;
+        if (burst_remaining_ms_ == 0 && (SCAN_ONGOING || TAIL_ACTIVE) && params_.vhs_burst_per_sec > 0 && params_.vhs_burst_duration_ms > 0) {
             const float P = (static_cast<float>(params_.vhs_burst_per_sec) / 1000.0F) * static_cast<float>(delta_ms);
             std::uniform_real_distribution<float> dist01(0.0F, 1.0F);
             if (dist01(rng_) < P) {
@@ -86,6 +92,17 @@ namespace Effects {
         if (flash_remaining_ms_ > 0) {
             flash_remaining_ms_ = std::max(0, flash_remaining_ms_ - delta_ms);
         }
+
+        // 5) Glitch tail: arranca un sol cop quan el scan ha acabat i el
+        //    flash s'ha esgotat. Si no hi havia flash configurat, també
+        //    arranca tot just acabar el scan.
+        if (!tail_started_ && elapsed_ms_ >= params_.duration_ms && flash_remaining_ms_ <= 0 && params_.tail_glitch_ms > 0) {
+            tail_started_ = true;
+            tail_remaining_ms_ = params_.tail_glitch_ms;
+        }
+        if (tail_remaining_ms_ > 0) {
+            tail_remaining_ms_ = std::max(0, tail_remaining_ms_ - delta_ms);
+        }
     }
 
     auto ScanReveal::isActive() const -> bool {
@@ -94,8 +111,12 @@ namespace Effects {
 
     auto ScanReveal::isFinished() const -> bool {
         if (params_.duration_ms <= 0) { return true; }
-        // Acabat = scan al final + flash exhaurit (o sense flash).
-        return elapsed_ms_ >= params_.duration_ms && flash_remaining_ms_ <= 0;
+        // Acabat = scan al final + flash exhaurit + glitch tail
+        // exhaurit (o sense tail configurat).
+        const bool SCAN_DONE = elapsed_ms_ >= params_.duration_ms;
+        const bool FLASH_DONE = flash_remaining_ms_ <= 0;
+        const bool TAIL_DONE = (params_.tail_glitch_ms <= 0) || (tail_started_ && tail_remaining_ms_ <= 0);
+        return SCAN_DONE && FLASH_DONE && TAIL_DONE;
     }
 
     void ScanReveal::render(const Surface& src, int x, int y) const {
@@ -118,15 +139,21 @@ namespace Effects {
         const int TIME_BUCKET = elapsed_ms_ / JITTER_TIME_BUCKET_MS;
         const int BURST_Y_PX = static_cast<int>(burst_y_norm_ * static_cast<float>(H));
         const bool BURST_ACTIVE = burst_remaining_ms_ > 0;
+        // Durant el glitch tail post-flash, BAND_TOP queda just damunt
+        // del peu del logo, fet que (amb el codi de jitter que segueix)
+        // generaria jitter residual a les últimes files. Aquí el
+        // suprimim explícitament: el tail només viu de bursts VHS.
+        const bool TAIL_ACTIVE = tail_started_ && tail_remaining_ms_ > 0;
 
         // Render fila a fila (només files revelades).
         for (int row = 0; row <= BAND_BOT && row < H; ++row) {
             int dx = 0;
 
             // Jitter de banda: amplitud màxima a la banda, falloff
-            // lineal cap als marges del radi de glitch.
+            // lineal cap als marges del radi de glitch. Inactiu durant
+            // el glitch tail (no hi ha banda).
             const int DIST_TO_BAND = std::abs(row - BAND_TOP);
-            if (params_.glitch_band_radius_px > 0 && DIST_TO_BAND <= params_.glitch_band_radius_px && params_.glitch_amplitude_px > 0) {
+            if (!TAIL_ACTIVE && params_.glitch_band_radius_px > 0 && DIST_TO_BAND <= params_.glitch_band_radius_px && params_.glitch_amplitude_px > 0) {
                 const float FALLOFF = 1.0F - (static_cast<float>(DIST_TO_BAND) / static_cast<float>(params_.glitch_band_radius_px));
                 const float JIT = rowJitter(row, TIME_BUCKET);
                 dx += static_cast<int>(std::lround(