Folds the actionable follow-requests surface into the Notifications page
as a Requests tab (alongside the existing Activity tab), so the navbar
exposes a single bell instead of two adjacent inboxes. The Requests tab
shows a count badge for pending rows regardless of read state, while the
bell badge keeps reflecting the unread-notifications count (which already
covers `follow_request_received` rows). The standalone /follows/requests
URL is preserved as a 301 redirect so prior notification deep-links,
emails, and bookmarks still resolve.
Driven by the IA review captured in docs/information-architecture.md.
Specs (notifications, social-follows, journal-landing) are updated in
the same change to reflect the new structure.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>