docs: add the npm packages to Get started and the home page (#88)

<!-- claude-projects-attribution: {"github_login":"shenxianpeng"} -->

## Summary

`@cpp-linter/clang-format` and `@cpp-linter/clang-tidy` are now on npm
for LLVM 12 to 23
([clang-tools-npm](https://github.com/cpp-linter/clang-tools-npm)).

- Get started, "Just the clang tools": a new row for the npm packages,
and the intro names them among the tools that use the static binaries.
- Home page: the "Just the clang tools" card says "via pip, npm or
asdf", and the footer's Tools list links the npm packages.

## Related Issues

None.

Co-authored-by: Xianpeng Shen <3353385+shenxianpeng@users.noreply.github.com>

Author: shenxianpeng

docs/getting-started.md

@@ -107,14 +107,15 @@ is in release candidates. Use the Python package until 2.0 is released.
 ## Just the clang tools
 
 These install `clang-format`, `clang-tidy` and other LLVM tools without building LLVM. clang-tools,
-asdf and the Homebrew tap use the same
+the npm packages, asdf and the Homebrew tap use the same
 [static binaries](https://cpp-linter.github.io/clang-tools-static-binaries/). Their
 download page links every file, shows which versions LLVM, PyPI, conda-forge and Homebrew
 have, and explains how to check a download.
 
 | Package | LLVM | Runs on | Install |
 | --- | --- | --- | --- |
 | [clang-tools](https://cpp-linter.github.io/clang-tools-pip/) | 12 to 23 | Linux, macOS, Windows | `pip install clang-tools`, then `clang-tools install clang-format clang-tidy --version 21` |
+| [npm packages](https://github.com/cpp-linter/clang-tools-npm) | 12 to 23 | Linux, macOS, Windows on x86-64 and ARM64 | `npm install --save-dev @cpp-linter/clang-format@21 @cpp-linter/clang-tidy@21`, then `npx clang-tidy` |
 | [asdf plugin](https://github.com/cpp-linter/asdf-clang-tools) | 12 to 23 | wherever asdf runs | `asdf plugin add clang-format https://github.com/cpp-linter/asdf-clang-tools.git` |
 | [Homebrew tap](https://github.com/cpp-linter/homebrew-tap) | 19 to 23 | macOS only | `brew install cpp-linter/tap/clang-format@21` |
 | [Static binaries](https://cpp-linter.github.io/clang-tools-static-binaries/) | 12 to 23 | Linux, macOS, Windows on x86-64 and ARM64 | download one file from the download page |

docs/overrides/home.html

@@ -165,7 +165,7 @@ <h1 class="cl-hero__title">
       },
       {
         "title": "Just the clang tools", "name": "clang-tools", "icon": "octicons/package-24",
-        "text": "clang-format, clang-tidy and friends for LLVM 12 to 23 via pip or asdf, plus Docker images (up to 22) and a macOS Homebrew tap (19 to 23).",
+        "text": "clang-format, clang-tidy and friends for LLVM 12 to 23 via pip, npm or asdf, plus Docker images (up to 22) and a macOS Homebrew tap (19 to 23).",
         "code": "pip install clang-tools\nclang-tools install clang-format clang-tidy --version 21",
         "href": "https://cpp-linter.github.io/clang-tools-pip/", "cta": "Read the docs",
       },
@@ -454,6 +454,7 @@ <h2>Maintained by two volunteers</h2>
           <a href="https://cpp-linter.github.io/cpp-linter/">Python CLI</a>
           <a href="https://cpp-linter.github.io/clang-tools-pip/">clang-tools</a>
           <a href="https://cpp-linter.github.io/clang-tools-static-binaries/">Static binaries</a>
+          <a href="https://github.com/cpp-linter/clang-tools-npm">npm packages</a>
           <a href="https://hub.docker.com/r/xianpengshen/clang-tools">Docker images</a>
         </nav>
         <nav aria-label="Learn">