Add buildPaginationModel and ctx.assetHref, and bump the plugin contract to 0.5.0

CHANGELOG.md

@@ -6,6 +6,25 @@ at boot. Entries start at 0.3.0.
 
 ## Unreleased
 
+### Plugin contract 0.5: set `apiVersion` to `"0.5.0"`
+
+The host's contract version is now 0.5.0, so discovery refuses a plugin whose `apiVersion` is still
+`0.4.x`. Change the literal in each plugin's manifest when you upgrade; nothing else in a 0.4 plugin
+needs to change.
+
+### `buildPaginationModel` builds the pagination partial's model
+
+`buildPaginationModel(page, hrefFor, { label?, pageSizes? })` from `@plainpages/plugin-api` turns
+`paginate()`'s result into what `partials/pagination` renders. `hrefFor(n)` is your list's URL on
+page n, and the rows-per-page form carries the same list state as the links. It replaces the hand-written
+mapping a list page needed.
+
+### A plugin can version its own `/public/` files
+
+Wrap a script, image or other file your own markup links in `assetHref("/public/<id>/…")` in a view,
+or `ctx.assetHref(…)` in a handler. The href gets the file's content hash, and the browser caches the
+file for a year instead of revalidating it every five minutes.
+
 ### Discovery warns when a gate names a permission no plugin declares
 
 A route or nav node that gates on a permission no installed plugin declares now logs a boot warning