feat(ui): add follow button, follows card, and inbox page

README.md

@@ -140,6 +140,11 @@ To Be Played is split into three repositories:
   automatic hint for 7 days, "Do not show again" for good, the 30 s auto close only for this browser session.
   Admins turn each on or off on `/admin/hints`. Hint and news text may use `**bold**` and `[text](url)` (an app
   path or https; anything else stays plain text); `HintText` renders React elements, never HTML.
+- **Follow users** (#27): a logged-in visitor follows the owner of a public profile with "Follow" on `/u/<name>`; the
+  settings page lists who you follow ("Unfollow") and who follows you ("Remove", a private follower shows as "Private
+  user"). Core writes one inbox note per followed user and batch (new games, achievements, status changes, wishlist
+  adds; what the profile hides is left out). `/inbox` (bell in the header, with the unread count) lists the newest 50 notes
+  and marks them read; a user who goes private ends the follow with a note. Notes older than 90 days are deleted.
 - **What's new**: a dialog on the dashboard shows the news entries the user has not seen yet, newest first. "Got it"
   marks them seen in Auth; closing the dialog any other way shows them again on the next dashboard visit. `/whats-new`
   (menu) lists all entries and marks them seen. Admins publish, preview, edit and delete entries on `/admin/news`.