a9411c1080
Validates that all 140 CSS custom properties from the expanded DEFAULT_VAULT_THEME_VARS are applied to the DOM when a theme is activated, including editor, heading, list, checkbox, inline-style, code-block, blockquote, table, and horizontal-rule properties. Also updates mock content and handlers to use the full 140-property frontmatter, matching the Rust backend output. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>