Import code examples from files for website

[dannywillems]

Description

Website code examples should be imported from actual source files that are compiled, similar to how o1-labs/mina-rust handles documentation.

Current State

Code examples in doc/docs/*.md are inline and may become stale.

Desired State

1. Create example files in a doc/examples/ directory
2. Examples are compiled as part of CI
3. Docusaurus imports from these files

Implementation Options

1. Use Docusaurus code import feature: @include "../../examples/basic.rs"
2. Use rustdoc and link to it
3. Use a build script to inject code

References

• o1-labs/mina-rust documentation approach