Provide an official PDF download for the Spring AI reference documentation

Description

The Spring AI reference documentation is currently available only as HTML at
https://docs.spring.io/spring-ai/reference/. Unlike many other Spring projects (Spring Boot, Spring Framework, Spring Data, …) there is no “PDF” button or downloadable spring‑ai‑reference.pdf file.

Why a PDF is needed

• Offline reading – many developers work in environments without reliable internet access (air‑gapped labs, conference Wi‑Fi, etc.).
• Print‑friendly – teams often print the docs for quick reference or for internal training.
• Parity with other Spring projects – a PDF link already exists for Spring Boot, Spring Framework, Spring Data, etc.; having a PDF for Spring AI would keep the documentation experience consistent across the Spring ecosystem.
• Stable citation – a fixed‑version PDF provides a stable reference for books, blogs and academic papers.

Suggested implementation

The Spring AI docs are written in AsciiDoc (spring-ai-docs/src/main/asciidoc/).

• Add a Gradle/Maven task (similar to the one used for other Spring projects) that generates spring-ai-reference.pdf from the AsciiDoc sources.
• Publish the file alongside the HTML docs at
  https://docs.spring.io/spring-ai/reference/pdf/spring-ai-reference.pdf
  (the same URL pattern used by other Spring projects).
• Update the docs navigation bar to show a small “PDF” link/icon, as done for Spring Boot and Spring Framework.

Affected version(s)

Request applies to the current stable release (e.g. 1.1.x) and all future releases.

Additional context

• An existing discussion on the absence of PDFs for newer Spring projects can be found in the Spring Framework issue tracker: https://github.com/spring-projects/spring-framework/issues/32907 (PDF version not generated for latest releases).
• The Spring AI documentation source is already version‑controlled, so generating a PDF is a straightforward add‑on.

Desired outcome

• A PDF download link that works for every released version of Spring AI.
• Optionally, the PDF should be included in the Maven Central “spring‑ai‑docs” artifact so users can fetch it with mvn dependency:get -Dartifact=org.springframework.ai:spring-ai-docs:1.1.0:pdf.

Thank you for considering this request!

Start in spring-ai-docs/src/main/asciidoc/ and inspect how the documentation navigation bar and release publication are configured. Compare the PDF generation and navigation patterns used by Spring Boot and Spring Framework. Done means a spring-ai-reference.pdf is published for every released version, with a working PDF link in the documentation.