feat: add rust link a

__ffi/rust_link_a/justfile

@@ -0,0 +1,21 @@
+_:
+  @just --list
+
+# generage .rs
+create-rs:
+  bindgen hello.h -o src/hello.rs
+
+# create .a file
+create-ar:
+  gcc -c -o hello.o hello.c
+  ar -cr libhello.a hello.o
+
+# re-run
+re-run:
+  rm hello.o || true
+  rm libhello.a || true
+  rm -rf target/ || true
+  @just create-ar
+  @just create-rs
+  cargo r
+