docs: update CLAUDE.md and README.md for v2.5.0

Document unified item processing pipeline (gotcha #23), parameterized
infinite scroll component (gotcha #24), quote embeds (gotcha #25).
Update architecture tree with new modules and controllers. Expand
route table and admin UI pages with explore, tag timeline, post detail,
and API endpoints. Add reader features (explore, hashtags, quotes,
link previews, read tracking, infinite scroll) to README.

Confab-Link: http://localhost:8080/sessions/e9d666ac-3c90-4298-9e92-9ac9d142bc06

README.md

@@ -14,13 +14,23 @@ ActivityPub federation endpoint for [Indiekit](https://getindiekit.com), built o
 - Configurable actor type (Person, Service, Organization, Group)
 
 **Reader**
-- Timeline view showing posts from followed accounts
+- Timeline view showing posts from followed accounts with tab filtering (notes, articles, replies, boosts, media)
+- Explore view — browse public timelines from any Mastodon-compatible instance
+- Cross-instance hashtag search — search a hashtag across multiple fediverse instances
+- Tag timeline — view and follow/unfollow specific hashtags
+- Post detail view with threaded context
+- Quote post embeds — quoted posts render as inline cards with author, content, and timestamp (FEP-044f, Misskey, Fedibird formats)
+- Link preview cards via Open Graph metadata unfurling
 - Notifications for likes, boosts, follows, mentions, and replies
 - Compose form with dual-path posting (quick AP reply or Micropub blog post)
 - Native interactions (like, boost, reply, follow/unfollow from the reader)
 - Remote actor profile pages
 - Content warnings and sensitive content handling
 - Media display (images, video, audio)
+- Infinite scroll with IntersectionObserver-based auto-loading
+- New post banner — polls for new items and offers one-click loading
+- Read tracking — marks posts as read on scroll, with unread filter toggle
+- Popular accounts autocomplete in the fediverse lookup bar
 - Configurable timeline retention
 
 **Moderation**
@@ -220,7 +230,11 @@ All admin pages are behind IndieAuth authentication:
 | Page | Path | Description |
 |---|---|---|
 | Dashboard | `/activitypub` | Overview with follower/following counts, recent activity |
-| Reader | `/activitypub/admin/reader` | Timeline from followed accounts |
+| Reader | `/activitypub/admin/reader` | Timeline from followed accounts (tabbed: notes, articles, replies, boosts, media) |
+| Explore | `/activitypub/admin/reader/explore` | Browse public timelines from Mastodon-compatible instances |
+| Hashtag Explore | `/activitypub/admin/reader/explore/hashtag` | Search a hashtag across multiple fediverse instances |
+| Tag Timeline | `/activitypub/admin/reader/tag?tag=name` | Posts filtered by a specific hashtag, with follow/unfollow |
+| Post Detail | `/activitypub/admin/reader/post?url=...` | Single post view with quote embeds and link previews |
 | Notifications | `/activitypub/admin/reader/notifications` | Likes, boosts, follows, mentions, replies |
 | Compose | `/activitypub/admin/reader/compose` | Reply composer (quick AP or Micropub) |
 | Moderation | `/activitypub/admin/reader/moderation` | Muted/blocked accounts and keywords |
@@ -329,6 +343,7 @@ This is not a bug — Fedify requires explicit opt-in for signed fetches. But it
 - **Single actor** — One fediverse identity per Indiekit instance
 - **No Authorized Fetch enforcement** — `.authorize()` disabled on actor dispatcher (see workarounds above)
 - **No image upload in reader** — Compose form is text-only
+- **No custom emoji rendering** — Custom emoji shortcodes display as text
 - **In-process queue without Redis** — Activities may be lost on restart
 
 ## License