pyvm: split op handlers into ops_core/ops_box/ops_ctrl; add ops_flow + intrinsic; delegate vm.py without behavior change

net-plugin: modularize constants (consts.rs) and sockets (sockets.rs); remove legacy commented socket code; fix unused imports
mir: move instruction unit tests to tests/mir_instruction_unit.rs (file lean-up); no semantic changes
runner/pyvm: ensure using pre-strip; misc docs updates

Build: cargo build ok; legacy cfg warnings remain as before

src/mir/builder/decls.rs

@@ -28,6 +28,9 @@ impl super::MirBuilder {
         // Look for the main() method
         let out = if let Some(main_method) = methods.get("main") {
             if let ASTNode::FunctionDeclaration { params, body, .. } = main_method {
+                // Also materialize a callable function entry "BoxName.main/N" for harness/PyVM
+                let func_name = format!("{}.{}", box_name, "main");
+                let _ = self.lower_static_method_as_function(func_name, params.clone(), body.clone());
                 // Convert the method body to a Program AST node and lower it
                 let program_ast = ASTNode::Program {
                     statements: body.clone(),