TIKA-4743 improve search and navigation on site

[tballison]

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[Copilot]

Pull request overview

This PR updates the Antora docs site UI to change how search is presented/loaded and adjusts the publishing script to match the expected deployed asset layout.

Changes:

• Reworked the header to conditionally render a search input (based on env.SITE_SEARCH_PROVIDER) and improved burger button ARIA attributes.
• Removed the custom Lunr search JS/CSS wiring from the supplemental UI.
• Updated publish-docs.sh to replace UI assets at publish/_ cleanly and to publish search-index.js at the site root.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
docs/supplemental-ui/partials/header-content.hbs	Moves/conditions the search input in the navbar and updates burger button ARIA attributes.
docs/supplemental-ui/partials/head-scripts.hbs	Removes custom search stylesheet injection.
docs/supplemental-ui/partials/footer-scripts.hbs	Removes custom search script injection.
docs/supplemental-ui/js/search.js	Deletes the custom Lunr search implementation.
docs/supplemental-ui/css/search.css	Deletes the custom search (and related) styling.
docs/publish-docs.sh	Fixes asset copying to avoid nested publish/_/_ and relocates search-index.js publish destination.
docs/modules/ROOT/pages/maintainers/release-guides/release-artifacts.adoc	Fixes the website update cross-reference to point at the current page.

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[Copilot]

Pull request overview

Copilot reviewed 8 out of 8 changed files in this pull request and generated 3 comments.