Macroforge MCP Server

## Side Effects: `{$do}` Execute an expression for its side effects without producing output. This is commonly used with mutable variables: Rust ``` let code = ts_template! {     {$let mut results: Vec<String> = Vec::new()}     {#for field in fields}         {$do results.push(format!("this.{}", field))}     {/for}     return [@{results.join(", ")}]; }; ``` Common uses for `{$do}`: * Incrementing counters: `{$do i += 1}` * Building collections: `{$do vec.push(item)}` * Setting flags: `{$do found = true}` * Any mutating operation