Tutorial: invalid crate-type syntax and inconsistent command-component example #376

The Create a command component section has two problems: an invalid Cargo configuration and a mismatch between the library-based instructions and the linked binary example.

1. Invalid crate-type syntax

The tutorial asks readers to create a library with cargo new --lib example and add:

[lib]
crate-type = "cdylib"

Running cargo metadata --no-deps --format-version 1 --offline in that project fails with:

error: invalid type: string "cdylib", expected a sequence

Reproduced with Cargo 1.98.1. The configuration should be:

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

2. The completed example uses a different entrypoint approach

The tutorial creates a library crate and asks readers to add export wasi:cli/run@0.2.7 to the app world. However, its linked completed example is a binary:

• src/main.rs uses an ordinary fn main().
• Cargo.toml has no [lib] configuration.
• The app world imports calculate but does not explicitly export wasi:cli/run.

Both approaches are valid, but copying that main() into the tutorial's library project does not implement the requested wasi:cli/run export. Fixing the manifest syntax alone does not resolve this mismatch.

The tutorial and completed example should use the same approach: either keep the cdylib instructions and provide the explicit run implementation and export, or use a binary project built for wasm32-wasip2, where Rust supplies the entrypoint for main().