feat: Add silkscreen text knockout fixture example

src/examples/2025/silkscreen/silkscreen-text-knockout.fixture.tsx

@@ -0,0 +1,79 @@
+import { Circuit } from "@tscircuit/core"
+import type React from "react"
+import { PCBViewer } from "../../../PCBViewer"
+
+export const SilkscreenTextKnockout: React.FC = () => {
+  const circuit = new Circuit()
+
+  circuit.add(
+    <board width="20mm" height="15mm">
+      <footprint>
+        {/* Regular silkscreen text for comparison */}
+        <silkscreentext
+          text="REGULAR"
+          pcbX={-5}
+          pcbY={3}
+          anchorAlignment="center"
+          fontSize={0.8}
+          layer="top"
+        />
+
+        {/* Knockout silkscreen text with default padding */}
+        <silkscreentext
+          text="KNOCKOUT"
+          pcbX={-5}
+          pcbY={0}
+          anchorAlignment="center"
+          fontSize={0.8}
+          layer="top"
+          isKnockout={true}
+        />
+
+        {/* Knockout text with custom padding */}
+        <silkscreentext
+          text="PADDED"
+          pcbX={-5}
+          pcbY={-3}
+          anchorAlignment="center"
+          fontSize={0.8}
+          layer="top"
+          isKnockout={true}
+          knockoutPadding="0.5mm"
+        />
+
+        {/* Knockout text on bottom layer */}
+        <silkscreentext
+          text="BOTTOM"
+          pcbX={5}
+          pcbY={0}
+          anchorAlignment="center"
+          fontSize={0.8}
+          layer="bottom"
+          isKnockout={true}
+        />
+
+        {/* Rotated knockout text */}
+        <silkscreentext
+          text="ROTATED"
+          pcbX={5}
+          pcbY={3}
+          anchorAlignment="center"
+          fontSize={0.8}
+          layer="top"
+          isKnockout={true}
+          pcbRotation={45}
+        />
+      </footprint>
+    </board>,
+  )
+
+  const soup = circuit.getCircuitJson()
+
+  return (
+    <div style={{ backgroundColor: "black" }}>
+      <PCBViewer circuitJson={soup as any} />
+    </div>
+  )
+}
+
+export default SilkscreenTextKnockout