Add shard activity feed + admin live feed; fix public-feed leak

Front ends for the rest of the sidecar data, plus a security fix the live data
surfaced.

- lib/shardEvents.js: shared describe()/category/label for every event kind
  (sales, deaths & PvP, skills, fame/karma, quests, world, and staff kinds).
- Public /site/shard/activity (ShardActivity): the full event log with category
  filter tabs and a live tail (history + SSE merged, de-duped). Linked from the
  Shard page. Shard page now reuses the shared describe().
- Admin: a "Live feed (all events)" panel on the Shard admin page subscribing to
  the admin SSE channel — shows every kind incl. audit/cheat/login attempts.
  useShardFeed generalized to take a stream url; api.adminShardStreamUrl added.

Security fix: GET /public/shard/feed now restricts to the public-safe kind
allowlist (shardEvents.list gains a `kinds` IN-filter). Previously it returned
whatever was logged — including audit.* / cheat.* / link.request. Those are
still stored for the admin channel but never served publicly (verified: a
public request for audit.command returns 0 rows).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011qPmpmVH1xGCiZoz9m9vW3

client/src/api/client.js

@@ -96,9 +96,11 @@ export const api = {
     idoc: () => req('/public/shard/idoc'),
     char: (serial) => req(`/public/shard/char/${encodeURIComponent(serial)}`),
   },
-  // Full path (incl. /api/v1) for the browser EventSource — the req() wrapper is
-  // fetch-only, so SSE subscribers build the URL from here.
+  // Full paths (incl. /api/v1) for the browser EventSource — the req() wrapper is
+  // fetch-only, so SSE subscribers build the URL from here. The admin stream
+  // carries every kind (incl. audit/cheat) and needs the staff session cookie.
   shardStreamUrl: `${BASE}/public/shard/stream`,
+  adminShardStreamUrl: `${BASE}/admin/uo-link/stream`,
 
   // ----- admin -----
   admin: {