Render Javadoc descriptions safely and ignore block tags

[baev]

Context

This fixes #1039 by changing how @Description(useJavaDoc = true) is resolved. Instead of taking raw Javadoc text and treating it like HTML, we now render the main Javadoc body into safe plain text / markdown and stop at block tags such as @param, @return, @throws, @see, @since, @version, and friends. In practice, that means Javadoc descriptions stay useful in the report, but they no longer leak metadata sections or create an XSS surface through descriptionHtml.

The new renderer supports the parts of Javadoc people actually use in descriptions: {@code}, {@literal}, {@link}, {@linkplain}, paragraphs, line breaks, lists, code spans, entities, and Unicode text. Unsupported or malformed constructs are intentionally degraded to safe text instead of being interpreted as markup. Javadoc-backed descriptions now go to description, not descriptionHtml, while explicit HTML descriptions remain unchanged. The allure.description.javadoc.separateLines option is still supported and now uses markdown-friendly line breaks.

I also added broader regression coverage around the processor and adapters, including negative cases, malformed HTML, Unicode, multiline inline tags, unsupported standard tags, and a more realistic modern Javadoc example. The current runtime coverage is in place for JUnit 4, JUnit Platform, and TestNG, and the renderer itself now has focused unit tests so future changes are easier to review.

Example:

/**
 * Verifies token refresh for expired sessions.
 *
 * <p>Use {@code refreshToken} from {@link AuthClient}.</p>
 * <ul>
 *   <li>Handles Unicode: café, Привет, 東京</li>
 *   <li>Escapes raw HTML like <script>alert(1)</script></li>
 * </ul>
 *
 * @throws IllegalStateException when refresh fails
 */
@Description(useJavaDoc = true)
@Test
void shouldRefreshExpiredSession() { ... }

Now the report description contains only the useful body content, rendered safely, and does not include the @throws section or raw HTML.

Checklist

• Sign Allure CLA
• Provide unit tests