fix(style): Z-Design V5 - Blend fijo sin compensación perceptual

Simplificación consensuada:
- Eliminar compensación perceptual (causaba más problemas)
- Blend fijo para TODOS los colores:
  - Focus: 18% base / 82% negro
  - Unfocus: 6% base / 94% negro

La fluidez viene de pasar bg_transition.current a widgets,
no de compensar matemáticamente.

src/core/style.zig

@@ -1375,46 +1375,31 @@ pub const DerivedPanelColors = struct {
 
 /// Derive panel frame colors from a single base color.
 ///
-/// Z-Design V4: "El rojo es el estándar"
-/// - Colores brillantes (L > 0.2, ej: rojo): 22% color visible (el estándar bueno)
-/// - Colores oscuros (L <= 0.2, ej: azul): 35% color visible (boost para compensar)
+/// Z-Design V5: Sincronía Atmosférica (2025-12-31)
+/// - SIN compensación perceptual (causaba más problemas que soluciones)
+/// - Blend fijo y generoso para TODOS los colores:
+///   - Fondo con focus: 18% base / 82% negro
+///   - Fondo sin focus: 6% base / 94% negro
 ///
-/// El objetivo es que TODOS los paneles tengan la vibrancia del rojo.
-/// El azul debe "saltar" del negro tanto como lo hace el rojo.
-///
-/// Luminance L = 0.2126*R + 0.7152*G + 0.0722*B
-/// - Rojo puro: L ~= 0.21 (justo en el límite, usa estándar 22%)
-/// - Azul puro: L ~= 0.07 (muy bajo, usa boost 35%)
-/// - Verde puro: L ~= 0.72 (alto, usa estándar 22%)
+/// La clave de la fluidez está en pasar bg_transition.current a los widgets,
+/// NO en compensar matemáticamente los colores.
 pub fn derivePanelFrameColors(base: Color) DerivedPanelColors {
-    const L = base.perceptualLuminance();
-
-    // Z-Design V4: Threshold-based boost
-    // El rojo (~22%) es el estándar de "buena vibrancia"
-    // Colores oscuros como el azul necesitan más intensidad para verse igual
-    const blend_factor: f32 = if (L > 0.2)
-        0.22 // Estándar: colores brillantes (rojo, verde, amarillo)
-    else
-        0.35; // Boost: colores oscuros (azul, violeta)
-
-    // Convert to percentage for blendTowards (inverted: 100% = all black)
-    // focus: full blend, unfocus: half blend
-    const focus_pct: u8 = @intFromFloat((1.0 - blend_factor) * 100.0);
-    const unfocus_pct: u8 = @intFromFloat((1.0 - blend_factor * 0.5) * 100.0);
-
     const black = Color.soft_black;
 
+    // Blend fijo: 18% color con focus, 6% sin focus
+    // blendTowards(black, 82) = 18% base + 82% black
+    // blendTowards(black, 94) = 6% base + 94% black
     return .{
-        .focus_bg = base.blendTowards(black, focus_pct),
-        .unfocus_bg = base.blendTowards(black, unfocus_pct),
+        .focus_bg = base.blendTowards(black, 82),
+        .unfocus_bg = base.blendTowards(black, 94),
         .border_focus = base,
         .border_unfocus = base.darken(30),
         .title_color = base.lightenHsl(20),
     };
 }
 
-test "derivePanelFrameColors blue gets boost" {
-    // Pure blue has L ~= 0.07, which is < 0.2, so it gets 35% boost
+test "derivePanelFrameColors fixed blend" {
+    // Z-Design V5: All colors use same fixed blend (18% focus, 6% unfocus)
     const blue = Color.rgb(0, 0, 255);
     const derived = derivePanelFrameColors(blue);
 
@@ -1423,34 +1408,30 @@ test "derivePanelFrameColors blue gets boost" {
     try std.testing.expectEqual(blue.g, derived.border_focus.g);
     try std.testing.expectEqual(blue.b, derived.border_focus.b);
 
-    // Focus bg should have significant blue visible (35% boost)
-    // 35% of 255 = ~89, blended with soft_black (17,17,20)
-    try std.testing.expect(derived.focus_bg.b > 70); // Should be vibrant blue
+    // Focus bg: 18% blue + 82% soft_black(17,17,20)
+    // 0.18 * 255 + 0.82 * 20 = 45.9 + 16.4 = 62.3
+    try std.testing.expect(derived.focus_bg.b > 50);
+    try std.testing.expect(derived.focus_bg.b < 80);
 }
 
-test "derivePanelFrameColors red is standard" {
-    // Red has L ~= 0.21, which is > 0.2, so it gets standard 22%
+test "derivePanelFrameColors same blend for all colors" {
+    // V5: No perceptual correction - same blend for red and blue
+    const blue = Color.rgb(0, 0, 255);
     const red = Color.rgb(255, 0, 0);
-    const derived = derivePanelFrameColors(red);
-
-    // Focus bg should have standard red visibility (22%)
-    // 22% of 255 = ~56, blended with soft_black
-    try std.testing.expect(derived.focus_bg.r > 40);
-    try std.testing.expect(derived.focus_bg.r < 100); // Not too bright
-}
-
-test "derivePanelFrameColors threshold behavior" {
-    // Test that blue (L < 0.2) gets MORE visibility than red (L > 0.2)
-    const blue = Color.rgb(0, 0, 255); // L ~= 0.07
-    const red = Color.rgb(255, 0, 0);  // L ~= 0.21
 
     const blue_derived = derivePanelFrameColors(blue);
     const red_derived = derivePanelFrameColors(red);
 
-    // Blue gets 35% blend, red gets 22%
-    // So blue's color channel should be proportionally MORE visible
-    // Blue: 35% of 255 ~= 89
-    // Red: 22% of 255 ~= 56
-    // Blue should have higher relative intensity
-    try std.testing.expect(blue_derived.focus_bg.b > red_derived.focus_bg.r);
+    // Both should have ~18% of their primary color channel
+    // Blue: ~18% of 255 = ~46, Red: ~18% of 255 = ~46
+    // (plus soft_black contribution)
+    const blue_intensity = blue_derived.focus_bg.b;
+    const red_intensity = red_derived.focus_bg.r;
+
+    // Should be approximately equal (within tolerance for soft_black blend)
+    const diff = if (blue_intensity > red_intensity)
+        blue_intensity - red_intensity
+    else
+        red_intensity - blue_intensity;
+    try std.testing.expect(diff < 10); // Close enough
 }