chore: initialize workspace and main project with standard structure

01.workspace/heave/Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "heave"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]

01.workspace/heave/src/lib.rs

@@ -0,0 +1,8 @@
+use std::*;
+
+mod fun;
+mod imp;
+mod mcr;
+mod str;
+mod trt;
+mod tst;