docs: update README.adoc for removed build.sh and new deploy script

Remove reference to deleted build/scripts/build.sh asciidoctor
alternative. Update deploy script reference from .sh to .js.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: themr0c

README.adoc

@@ -56,17 +56,6 @@ The `ccutil` CLI tool reproduces the behavior of the production publication chai
 $  build/scripts/build-ccutil.sh
 ----
 
-[NOTE]
-====
-* To build with `asciidoctor` rather than `ccutil`, run the following script.
-The output will look differently and you might miss issues with content that cannot build in production.
-+
-[source,terminal]
-----
-$  build/scripts/build.sh
-----
-====
-
 ## Checking for broken links
 
 You can run `lychee` locally to check for broken links in your PR.
@@ -101,7 +90,7 @@ PRs have a link to the generated HTML attached as a comment.
 
 The publication workflow has two stages:
 
-. The link:.github/workflows/pr.yml[PR workflow] and link:.github/workflows/build-asciidoc.yml[GitHub Pages workflow] build HTML from AsciiDoc sources and push the output to the `gh-pages` branch using `build/scripts/deploy-gh-pages.sh`, which handles concurrent pushes with automatic retry.
+. The link:.github/workflows/pr.yml[PR workflow] and link:.github/workflows/build-asciidoc.yml[GitHub Pages workflow] build HTML from AsciiDoc sources and push the output to the `gh-pages` branch using `build/scripts/deploy-gh-pages.js`, which handles concurrent pushes with automatic retry, cleanup of stale PR/branch directories, and index regeneration.
 . The link:https://github.com/redhat-developer/red-hat-developers-documentation-rhdh/actions/workflows/pages/pages-build-deployment[GitHub Pages build and deployment] workflow, managed by GitHub, detects pushes to the `gh-pages` branch and publishes the content to GitHub Pages.
 
 ## Reviews