fix(events): staff could not reach their own participation history

Found by the live walk, signed in as an admin: /account/events redirected to
the dashboard. `GET /player/events/history` is behind requireAuth alone and
self-scoped on req.user.id -- staff are a superset of players -- but the WEB
has two logged-in shells, and RequirePlayer sends anyone who is not a
`player` out of /account. A single mount there is a screen the reviewing
admin can never open.

Engagement Phase 7 hit this exact wall with the inbox and answered it with
two routes, one pair of components and one mapping. `eventHistoryPath` joins
`inboxPath` and `notificationSettingsPath` in notificationPaths.js rather
than starting a second file with the same comment at the top of it. The
staff path is /admin/events/mine, in the Events section of the sidebar, and
it is the one row in that group with no `roles`.

Also: the eventAnnounce fixture carried no slug, state or `listed`, so
`eventUrl` answered undefined in every test in that file and the new code
was exercised by none of them. The fixture now looks like a definition row,
and three tests cover the link, the unlisted case and the draft case.

The run.failed assertion that came with them was reading the wrong layer:
`baseFor` assembles eventUrl for every trigger and the SEAM drops the keys a
trigger does not declare, so the declaration test is what proves it. Removed,
with a note saying where the rule actually lives.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016wDDVXWMDz82WqE1i969r4

client/src/App.jsx

@@ -262,6 +262,15 @@ export default function App() {
                   two paths; `lib/notificationPaths.js` is the one mapping. */}
               <Route path="notifications" element={<PlayerInbox />} />
               <Route path="notifications/settings" element={<PlayerNotifications />} />
+              {/* And participation history, for the same reason and by the same
+                  arrangement (Phase 14a): `/player/events/history` is behind
+                  requireAuth alone, so a staff member has one — but
+                  `RequirePlayer` sends them out of `/account`. Declared BEFORE
+                  `events/:id`, though it need not be: a static segment outranks
+                  a dynamic one whatever the order, which is the rule that made
+                  `events/new` unreachable for seven phases. Written in the order
+                  it resolves. */}
+              <Route path="events/mine" element={<PlayerEvents />} />
               {/* Installed modules' admin pages, at /admin/<id>/…, already inside
                   RequireAuth + AdminLayout. A module cannot supply its own auth
                   wrapper — only an optional { roles }, which core applies as the