lock screen: threat vignette + chromatic aberration on failed auth, heartbeat pulse at 3+ fails

shell/modules/lock_threat.frag

@@ -0,0 +1,52 @@
+#version 440
+
+layout(location = 0) in vec2 qt_TexCoord0;
+layout(location = 0) out vec4 fragColor;
+
+layout(std140, binding = 0) uniform buf {
+    mat4 qt_Matrix;
+    float qt_Opacity;
+    // 0.0 = no threat, 1.0 = max lockout
+    float uThreat;
+    // 0.0-1.0 heartbeat pulse (0 when inactive)
+    float uPulse;
+    // accent/threat color
+    vec4 uColor;
+};
+
+layout(binding = 1) uniform sampler2D source;
+
+void main() {
+    vec2 uv = qt_TexCoord0;
+    float threat = clamp(uThreat, 0.0, 1.0);
+    float pulse = clamp(uPulse, 0.0, 1.0);
+
+    // Combined intensity: base threat + heartbeat spike
+    float intensity = threat + pulse * threat * 0.4;
+
+    // Chromatic aberration - RGB channel split increasing with threat
+    float aberration = intensity * 0.008;
+    float r = texture(source, uv + vec2(aberration, 0.0)).r;
+    float g = texture(source, uv).g;
+    float b = texture(source, uv - vec2(aberration, 0.0)).b;
+    float a = texture(source, uv).a;
+    vec4 tex = vec4(r, g, b, a);
+
+    // Vignette - radial darkening from edges, creeping inward with threat
+    vec2 center = uv - 0.5;
+    float dist = length(center * vec2(1.0, 0.7)); // wider horizontally
+    // Inner edge shrinks as threat rises (0.7 -> 0.25)
+    float vigInner = mix(0.7, 0.25, intensity);
+    // Outer edge also shrinks (1.0 -> 0.6)
+    float vigOuter = mix(1.0, 0.6, intensity);
+    float vig = smoothstep(vigInner, vigOuter, dist);
+
+    // Red tint on the vignette area
+    vec3 threatColor = uColor.rgb;
+    vec3 tinted = mix(tex.rgb, threatColor * 0.15, vig * intensity);
+
+    // Darken edges
+    tinted *= 1.0 - vig * intensity * 0.7;
+
+    fragColor = vec4(tinted, tex.a) * qt_Opacity;
+}