v1.5.1

Fixed

• guides.xml theme syntax - theme must be an attribute on <guides>, not a child element
  • ❌ Wrong: <theme name="typo3docs" />
  • ✅ Correct: <guides theme="typo3docs">
• schemaLocation URL - docs.typo3.org schema URL returns 404, use vendor path instead
• Added root attributes documentation (theme, links-are-relative)