Add C# implementation

src/main.rs

@@ -2,6 +2,7 @@ use anyhow::Result;
 use clap::{Parser, Subcommand};
 use libjrpc::{
     targets::{
+        csharp::CSharpCompiler,
         rust::RustCompiler,
         typescript::{Node, TypeScriptCompiler},
     },
@@ -67,6 +68,7 @@ pub fn main() -> Result<()> {
                     "ts-esm" => {
                         libjrpc::targets::compile::<TypeScriptCompiler<Node>>(ir, output_dir)?
                     }
+                    "csharp" => libjrpc::targets::compile::<CSharpCompiler>(ir, output_dir)?,
                     _ => {
                         println!("Unsupported target: {}", output_target);
                     }
@@ -83,6 +85,7 @@ pub fn main() -> Result<()> {
             println!("rust");
             println!("ts-node");
             println!("ts-esm");
+            println!("csharp")
         }
     }