update names

[wilsonwang371]

This pull request renames and generalizes the Rust-based WASM samples to "WASM-JS" samples, reflecting a shift to a JS-first approach where JavaScript code is run via a Rust-based Boa JS runner compiled to WASM. The changes update documentation, Makefile logic, and sample directory structure to use wasm-js instead of wasm-rust, clarify build output locations, and ensure compatibility with previous variable names for smooth transition.

The most important changes are:

Build System and Output Structure:

• The Makefile logic is updated to use wasm-js and BUILD_JS_SAMPLES/JS_SAMPLES variables instead of wasm-rust and BUILD_RUST_SAMPLES/RUST_SAMPLES, with compatibility handling for old variable names. Build outputs are now placed in samples/build/js/ (with a compatibility copy in samples/build/rust/). [1] [2]

Documentation and Sample Directory Updates:

• All references in documentation and READMEs are updated from wasm-rust to wasm-js, describing the new JS-first approach using a Boa JS runner, and clarifying that the main output directory is now build/js/. [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16]

New Sample Directory:

• A new samples/wasm-js/README.md is added to explain the JS-first sample approach, where JavaScript code is executed via the WASM-compiled Boa JS runner.

Minor Code Change:

• A macro in samples/wasm-c/chat_completion.c is enabled, though this is unrelated to the main theme of the PR.