feat(app): daemon-sourced Event Center feed, read-model, bell badge

Source Event Center from daemon event_log (seed + live event/events_read push).
Unread/Errors tabs filter real EventRecord flags; bell shows numeric unread badge;
clicking an entry calls focusSurface + markEventsRead(ids). notify.ts param widened
to string so exit kind type-checks without breaking existing NOTIFY_STATES guard.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/src/TopBar.tsx

@@ -29,11 +29,12 @@ function IconBtn({ icon, onClick, active, title }: { icon: React.ReactNode; onCl
 }
 
 export function TopBar({
-  active, eventsOpen, onToggleEvents,
+  active, eventsOpen, onToggleEvents, unread,
 }: {
   active: WorkspaceView | null;
   eventsOpen: boolean;
   onToggleEvents: () => void;
+  unread: number;
 }) {
   return (
     <div
@@ -68,7 +69,19 @@ export function TopBar({
       <div style={{ display: "flex", alignItems: "center", gap: 6 }}>
         <IconBtn icon={<PanelRight size={15} />} onClick={onToggleEvents} active={eventsOpen} title="Toggle Event Center" />
         <IconBtn icon={<Search size={16} />} title="Search (mock)" />
-        <IconBtn icon={<Bell size={16} />} title="Notifications (mock)" />
+        <div style={{ position: "relative", display: "flex" }}>
+          <IconBtn icon={<Bell size={16} />} title="Notifications (mock)" />
+          {unread > 0 && (
+            <span style={{
+              position: "absolute", top: -2, right: -2, minWidth: 14, height: 14, padding: "0 3px",
+              borderRadius: 7, background: COLORS.stError, color: "#fff",
+              fontFamily: FONT.ui, fontSize: 9, fontWeight: 700,
+              display: "flex", alignItems: "center", justifyContent: "center", boxSizing: "border-box",
+            }}>
+              {unread > 99 ? "99+" : unread}
+            </span>
+          )}
+        </div>
         <IconBtn icon={<Settings size={16} />} title="Settings (mock)" />
         <span style={{ width: 1, height: 18, background: COLORS.borderStrong, margin: "0 2px" }} />
         <button