feat: map item type

places I've been, using the items framework; this gets us AP integration for free

these are kind of a type of blog post; I think we want long text bodies / support for one item per file, using yaml frontmatter + markdown body, where the body becomes a regular property of the item, as html

they would render into a map, clicking on a point loads more detail into a side panel (so it works best on desktop, idk what mobile looks like...)

they have tags and coloring rules, so we could have e.g. bell towers, restaurants, other significant places all be different colors

they have optional properties that we can pick up and render a special way in the pane, e.g. dove's guide tower IDs, URLs, maybe star ratings...? not all props will make sense for all items, even of the same type/tag

are they searchable somehow...? are items searchable more generally as in the bookmarks list?

Start by inspecting the existing items framework and the blog-post-like content model referenced in the issue. Determine how YAML frontmatter and Markdown bodies are currently handled, then clarify the map, side-panel, tagging, coloring, optional properties, and search requirements before implementation. Done means the agreed item type and its rendering behavior are documented and working.