TOML frontmatter interprets bare dates like 2022-10-31 as date literals
requiring time components, causing parsing issues. YAML handles dates
as strings by default, avoiding these problems.
Changes:
- export.ex: Add org-hugo-front-matter-format set to yaml
- index.ex: Update title regex to match YAML format (title: vs title =)
- quartz.config.ts: Use default FrontMatter plugin (YAML) instead of TOML
