importing first library for use in a second library - use of undeclared crate or module - error[E0432]: unresolved import

Question

I am trying to import and use a library I made myself in rust into another library I made in rust for wasm web. The first library is my UI library. The second library that depends on the UI library is my Game library.

the directories are:

make/ui/src/lib.rs
make/ui/Cargo.toml 
make/game/src/lib.rs 
make/game/Cargo.toml

My UI library builds without error. and has the following Cargo.toml

[package]
name    = "ui"
version = "0.1.0"
edition = "2021"

[lib]
name       = "ui"
crate-type = ["cdylib"]

I link my Game library to my local UI library in my Game library's Cargo.toml with

[dependencies]
ui = {path = "../ui/", version="0.1.0"}

The following build command executed in make/game:

wasm-pack build --release --target web 

gives the compilation error: in make/game/src/lib.rs

use ui::*; 

error[E0432]: unresolved import ui ^^^^^ use of undeclared crate or module `ui

the make/ui/src/lib.rs begins like this

pub mod ui 
{
  struct UI_A {...}
  impl UI_A {...}
  //etc...
}

What's missing?

UPDATE I am able to get Game library to build if I replace 'use ui' with

use crate::ui::*;
#[path = "../../ui/src/lib.rs"] mod ui;

and if I also remove pub mod ui from make/ui/src/lib.rs so I just have

struct UI_A {...}
impl UI_A {...}
//etc...

(from one of the answers posted here: How can I include a module from another file from the same project?)

I just find this a bit odd, since the path is already described in Cargo.toml. Also, although 'it works' the way I'm using it depends on having access to the source code - so not ideal if I wanted to divy up work to a team of developers to just 'use' the library without having access to the library source code.

If this is the way, please let me know.