Add quantum computing playground

- Interactive circuit playground with sample circuits
- Multiple export formats and visualization
- Production mode compatibility

Author: Fermious

_layouts/qc-playground.html

@@ -0,0 +1,33 @@
+---
+layout: qc-playground
+icon: fas fa-microchip
+order: 4
+title: QC Playground
+---
+
+# Quantum Circuit Playground
+
+Interactive quantum circuit simulator powered by [Q.js](https://quantumjavascript.app). Build, visualize, and experiment with quantum circuits directly in your browser.
+
+## Features
+
+- **Text-based circuit editor** - Write quantum circuits using Q.js's intuitive syntax
+- **Visual circuit diagrams** - See your circuits rendered as interactive diagrams
+- **Probability analysis** - View measurement outcomes and quantum state probabilities
+- **Export options** - Generate ASCII diagrams, LaTeX code, and plain text representations
+- **Sample circuits** - Learn from pre-built examples including Bell states and quantum algorithms
+
+## Getting Started
+
+1. Type or paste your quantum circuit in the text area below
+2. Click "Apply" to render the circuit and see results
+3. Experiment with the sample circuits provided
+4. Export your circuits for use in documentation or presentations
+
+Start with something simple like a Bell state:
+```
+H-X#0
+I-X#1
+```
+
+Or try the loaded example circuit to see how entanglement works!