Create real-world examples and demos

[LynnColeArt]

Build compelling examples that show Sparkle in action:

• Distributed matrix multiplication
• Simple neural network training
• Image processing pipeline
• Cryptocurrency mining alternative (mine AI compute!)
• Visualization of mesh topology

Examples should work on diverse hardware and show the power of heterogeneous compute.

[LynnColeArt]

Progress Update: Created first examples!

✅ device_info.f90 - Shows device discovery and capabilities
✅ hello_sparkle.f90 - Complete working example demonstrating:

• Device discovery with friendly output
• Memory pool creation and allocation
• Work distribution planning
• The vision of democratizing AI compute

Next examples to create:

• Matrix multiplication across devices
• Collective operations demo
• Mesh topology visualization

[LynnColeArt]

Examples and demos added:

• ✅ Basic convolution examples (test_conv2d_*.f90)
• ✅ Performance comparison demos
• ✅ Device selection examples
• ✅ PM4 direct submission examples
• ✅ Benchmarking suite with detailed metrics

Still TODO:

• More real-world ML model examples
• Tutorial notebooks
• Video demos

This issue is about 60% complete.