Fedify's JSON-LD compaction collapses single-element arrays to plain
objects. Mastodon checks `attachment.is_a?(Array)` and silently skips
non-array values, causing profile links to never display.
Also adds profile links section to the my-profile admin page and
fixes rel=me on the public profile page for bidirectional verification.
- Notification view: tab navigation (Replies, Likes, Boosts, Follows, All)
with count badges; defaults to Replies tab; type filter in storage layer
with compound index for efficient queries
- My Profile admin page: profile header with avatar/stats/bio, tabbed
activity view (Posts, Replies, Likes, Boosts) pulling from posts,
ap_activities, and ap_interactions collections
- Reader: default tab changed from All to Notes
- Timeline cards: timestamps now link to post detail view
- Notification cards: Reply and View Thread buttons on reply/mention types
