Switches `listForUser` from page-offset to cursor (`before` param,
opaque base64 of `{ts, id}`) ordered by `(created_at DESC, id DESC)`
for stable pagination even with simultaneous fan-out inserts.
Returns `{ rows, nextCursor }` instead of a bare array. Loader surfaces
`?before=<cursor>` on a "Load older" link at the bottom of the list,
shown only while `nextCursor !== null`. Default page size 50, capped
at 100. Malformed cursors fall back to "start from top" rather than
400ing — opaque cursors should not be a client validation surface.
Spec drift: delta spec adds three pagination scenarios (cursor pages
forward, tie-stable on identical `created_at`, malformed-cursor
graceful fallback). Design doc gets a new decision section explaining
the cursor choice over page-offset and why we don't compute totals.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Adds the notifications system end-to-end (4 types, payload-versioned
JSONB, SSE-based live unread badge, /notifications page, mark-read API,
fan-out job for activity_published, daily 90-day retention purge).
Bell icon in the navbar with unread badge.
Side-findings from exercising the change:
- Add 6-digit magic code to registration (mirrors login UX, mobile
paste-friendly), with `[Register Magic Link]` console line in dev so
the code is reachable without a real email transport.
- Manual passkey/magic-link toggle on the register form (login already
had it).
- Restrict ALPN to http/1.1 in HTTPS dev so React Router's
singleFetchAction CSRF check (Origin vs. Host) passes — Node doesn't
synthesize Host from h2's :authority. Plain HTTP dev unaffected.
- Followers/Following routes now use the locked-account rule from the
profile route (owner + accepted followers see the list; others 404).
Profile page renders the count chips as plain spans for viewers who
can't see the lists, so private profiles don't surface dead links.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
