Add URP bridge cutout shader pass (#7109)

src/main/csharp/net/eagle0/clients/unity/eagle0/Assets/TileableBridgePack/Materials/BridgeUnlitCutout.shader

@@ -4,6 +4,56 @@ Shader "Eagle0/Bridge Unlit Cutout" {
         _MainTex("Albedo", 2D) = "white" {}
         _Cutoff("Alpha Cutoff", Range(0,1)) = 0.5
     }
+    SubShader {
+        Tags {
+            "Queue" = "AlphaTest"
+            "RenderType" = "TransparentCutout"
+            "RenderPipeline" = "UniversalPipeline"
+        }
+        LOD 100
+        Cull Off
+
+        Pass {
+            Name "UniversalForward"
+            Tags { "LightMode" = "UniversalForward" }
+
+            HLSLPROGRAM
+            #pragma vertex vert
+            #pragma fragment frag
+
+            #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl"
+
+            struct appdata {
+                float4 vertex : POSITION;
+                float2 uv : TEXCOORD0;
+            };
+
+            struct v2f {
+                float4 vertex : SV_POSITION;
+                float2 uv : TEXCOORD0;
+            };
+
+            TEXTURE2D(_MainTex);
+            SAMPLER(sampler_MainTex);
+            float4 _MainTex_ST;
+            half4 _Color;
+            half _Cutoff;
+
+            v2f vert(appdata v) {
+                v2f o;
+                o.vertex = TransformObjectToHClip(v.vertex.xyz);
+                o.uv = TRANSFORM_TEX(v.uv, _MainTex);
+                return o;
+            }
+
+            half4 frag(v2f i) : SV_Target {
+                half4 col = SAMPLE_TEXTURE2D(_MainTex, sampler_MainTex, i.uv) * _Color;
+                clip(col.a - _Cutoff);
+                return col;
+            }
+            ENDHLSL
+        }
+    }
     SubShader {
         Tags {
             "Queue" = "AlphaTest"