Nested categories like `on/tech` or `art/music` were being sent as-is
to ActivityPub consumers. Three fixes:
- status.js (Mastodon Client API): raw category used as tag name/URL
instead of the normalized last segment
- jf2-to-as2.js buildPlainTags/buildFedifyTags: href used
encodeURIComponent() on the full path, encoding the `/` separator
and producing broken category URLs (e.g. `categories/on%2Ftech`
instead of `categories/on/tech`)
Tag names are now consistently normalized to the last path segment
(`on/tech` → `#tech`). Category hrefs encode each segment individually
but preserve the `/` separator.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>